Worms and other parasites are a common occurrence for pets and free-roaming cats. If you take your pet into the vet for their annual exam, they always deworm your beloved companion every single year.
Worms can happen to even indoor-only cats, so it’s important to deworm them regularly and pay attention to their poop! Houses are not proof against rodents, insects, or other resident animals and all of those are common ways that worms are spread.
If they live with another cat, they can get parasites from ingesting fecal matter after visiting the litter box. If you own both cats and dogs, dogs who go outside often get parasites and can infect the cats that live with them.
The most common symptom of worms or other parasites in cats is NO symptoms. Do not assume just because your cat doesn’t have symptoms that they do not have worms. Most infected cats show very few symptoms if they show any at all.
Disclaimer: This post contains affiliate links. This simply means I earn a small commission on qualifying purchases. Please read Affiliate Disclosure for full details. Thanks for supporting the kitties!
If you work with community cats, a vet may not always be an option. It can also be majorly traumatic for feral cats to be taken in to the vet for routine care. So I listed some well-rated pharmacies outside of the US as well. However, always consult your vet before giving your cats any medication!
Roundworms (Toxocara species) are the most common internal parasite of cats, hands down. It is estimated that 25%-75% of cats are affected, with a higher rate of infection in kittens. Roundworms are comprised of many different species. The most common cat roundworm is Toxocara cati, but cats can also be infected by Toxocara canin (dog roundworm), Toxocaris leonina (cats, dogs, and foxes), and others. Roundworms can be transmitted to other species, including humans, although they don’t reproduce in other hosts.
Adult roundworms are 3-5 inches long, cream-colored, and live inside the cat’s intestines. They do not attach to the intestinal walls. They survive by eating the digested food ingested by the host animal, such as the cat. Adult roundworms produce eggs that are passed into the feces. The eggs require several days or several weeks to hatch into the infective larva stage.
Causes
Cats get infected by Toxocara cati by ingesting the eggs in fecal matter or eating infected animals (such as earthworms, roaches, rodents, and birds) that have roundworm larva in its tissues. Kittens get infected by ingesting larva through an infected queen’s milk. Infection by Toxocaris leonina occurs in adult cats the same way, but the larva does not pass in the infected mother’s milk, so kittens under 2 months old are rarely infected by T. leonina.
In adult cats, roundworm infection is usually relatively benign. However, in kittens, it can cause serious illness or even death.
Symptoms of roundworms
Roundworms are one of two parasitic worm infections that can be seen with the naked eye. Cats may vomit up adult worms or pass them in their stool occasionally. However, it is important to note that cats can show NO symptoms as well. It is very common, actually. Reinfection of a cat after treatment is super common, too.
The ONLY way to tell for certain if your cat is infected with roundworms (outside of seeing adult worms in feces or vomit), is by a microscopic examination of the stool where eggs are detected. Keep in mind, no symptoms does not equal no infection.
Toxocara species can infect humans, as well. Though they cannot reproduce as humans aren’t their primary host, they CAN infect humans, so it is vital to ensure your indoor cat or cat colony gets treated for roundworms.
Hookworms (Ancylostoma species) are another common intestinal parasite that infects dogs and cats. There are two main types of common cat hookworms, although cats can become infected with the canine and other species of hookworms in rare instances.
Hookworms are long-lived parasites and can even live as long as the cat! That’s twenty years in some cases, folks!
Hookworm infestations are not as common as roundworms in cats. The rate of infection depends a lot on geographical location. In general, hookworm infections can be more prevalent in dogs than cats, but it can still be a serious condition. Hookworm infection can be fatal in young kittens.
They get their name from their hook-like mouth parts that anchor into the intestinal wall. Hookworms feed on tissue fluids and the blood of their hosts.
Causes
So how do cats get hookworms? Immature hookworms (eggs and larva) can live in the soil for months. Cats can walk or dig in contaminated soil. The larva then they burrow into the skin or are ingested by cats during grooming. Kittens can get hookworms through their mother’s milk.
Hookworms are more common in moist, warm environments. Overcrowding and poor sanitation can also contribute to infection.
Symptoms of hookworms
Hookworm infections can be easily diagnosed with a fecal test at your veterinarian. Hookworms tend to pass a lot of eggs into the stool of cats, so it is easily detectable. Hookworms are NOT usually visible to the naked eye, so you will not see signs of worms in a cat’s poo.
Also, older cats may not show symptoms of hookworm infection while young kittens become fatally ill. If some kittens in a litter die, hookworm should always be suspected.
Feline and canine hookworms don’t usually infect humans, but they can burrow into human skin if you decide to walk barefoot over contaminated soil. However, humans have their own species-specific hookworms that can infect them, as well as zoonotic species of hookworms that can infect both cats and humans, but this type of hookworm infection is rare.
In the case of severe infestation, fluid therapy and blood transfusion may be required with hookworm infections.
There is no known preventative for roundworm or hookworm infection in cats. All medications given are to kill current infestations, not prevent reinfection. To help prevent the spread of worm infection in indoor cats, scoop and sanitize litter boxes frequently!
Tapeworms are another common parasite that cats (and dogs and people!) can get. There are many different species of tapeworms that cats can get, but the most common is Dipylidium caninum.
Tapeworms have a long flatted body that consists of segments. These segments are filled with eggs. Its flattened appearance is what gives this nasty parasite its name! Did you know that tapeworms can measure 24 inches or longer?!
Adult tapeworms live in the small intestine with its head embedded in the mucus membrane of the intestine, where it absorbs nutrients from its host. As the segments furthest from the head mature, they break off and pass into the feces of an infected animal. These segments can be seen sometimes in the feces or around a cat’s rectum. They look like small grains of rice or dried cucumber seeds. They can and do move on their own when fresh. Yuck!
Microscopic examination of feces may not always reveal tapeworm infection as eggs are only passed in groups in these segments.
While gross, tapeworm infection rarely causes significant illness in cats.
Cats become infected with tapeworms by ingesting fleas. This can happen by grooming themselves (or each other) or by eating infected rodents. Fleas and rodents become infected with tapeworms by ingesting eggs in the environment. Luckily, cats do not contract tapeworms by ingesting tapeworm eggs.
Controlling flea and rodent infestations is vital to controlling tapeworms, as reinfection is very common otherwise!
Related Post: What is the Best Flea Treatment for Cats?
It is rare for a human to catch tapeworms from their pets, but it is possible, especially for children. It does require that a human ingest an infected flea.
Other common tapeworms that cats can get belong to the Taenia group. These tapeworms require a cat eats infected rabbits, mice, and birds to become infected. Other possible tapeworm species include Echinococcus and Mesocestoides.
Tapeworms are not regularly identified in the usual fecal exams you can get at your veterinarian like roundworms and hookworms are. They only shed their eggs grouped in segments, so that is the usual method of diagnosis.
The most important part of controlling tapeworms in your cats (indoor or feral!) is to control the flea population! Flea preventative is the only way to eliminate infected fleas. Another way to help prevent tapeworms is to control the rodent population and to keep your cats indoors. Cats who are outside will hunt, and even if they are on flea medication, they will eat mice who often have fleas or tapeworms themselves.
If you take care of a colony of feral or community cats, you will not be able to control their hunting, but you can control their fleas. I highly suggest setting a bi-monthly or quarterly tapeworm deworming schedule, just to keep your beloved colony healthy.
Contrary to popular belief, heartworms can infect cats too!
While the main host for heartworms is dogs, it can infect cats, wolves, coyotes, foxes, ferrets, bears, seals, reptiles, and even rarely, humans!
This is one especially nasty parasite, people.
Heartworms (Dirofilaria immitis) spread from host to host through the bites of mosquitoes. These nasty parasites don’t just infect the heart, as their name suggests, but also lung arteries. Left untreated, heartworms are fatal in its host.
This fun parasite is now pretty common throughout the entire United States (and many other countries!) when it was at first limited to the warm, Southern states.
Transmission of heartworms is limited to warmer months as development in the mosquito is halted during cooler temperatures. It takes about 6-7 months for a dog to develop adult heartworms after first being infected.
I’m sorry to say, while heartworm disease may be cured in dogs, there is no effective treatment for cats infected with heartworms at this time. The medication used to treat heartworm infection in dogs is actually quite toxic for cats.
According to Wikipedia, the infection rate of cats is 1%-5% in the regions where heartworm disease is endemic. Both indoor and outdoor cats can be infected as mosquitoes enter homes quite easily.
Because cats are not the natural host for heartworms, most of the heartworm larva will die in cats. Cats tend to only be infected with a few heartworms (2-5 is typical), while dogs can have many. Adult heartworms don’t live as long in cats, as well. Cats are also more likely to aberrant migration of heartworm larva that results in heartworm infections in the brain or body cavities.
So what does this mean?
It means that cats get infected by an inflammatory issue called “heartworm-associated respiratory disease” and is caused by heartworm larva in lung arteries and vessels. It is also easy to misdiagnose it as asthma or bronchitis in cats. Cats are also more likely to die of obstructed arteries from dying worms than dogs are.
Now, here’s some good news!
Normally, a cat’s immune response is strong enough to fight off heartworm infection! That is why so few cats actually contract heartworm disease. It isn’t because they aren’t exposed. It is because they fight off the infection in normal circumstances because they are not the natural host for heartworms!
However, the immune response itself can cause some same symptoms of heartworm disease. And even if the infection is cleared up, there may be some lingering respiratory damage.
The only way to tell if your cat has contracted heartworm disease is with a couple of blood tests. The antigen blood test is not as reliable unless female adult heartworms are present in the cat. That means if there are only adult males or only larva heartworms (which cause MANY of the symptoms cats experience), the test will show up as a negative for heartworms. The antibody blood test is more reliable at picking up antibodies to heartworms if the cat has been exposed within the past 3 or so months. X-rays and echocardiography may also detect heartworm infections in cats.
There is no medication approved by the FDA to treat heartworm infection in cats. However, unlike dogs, cats don’t have an adverse reaction to heartworm preventative when infected.
So what is typically done for infected cats is to put the cat on a heartworm preventative, such as Ivermectin or Revolution, and a course of corticosteroids. The prognosis for cats infected with heartworms is guarded.
Never, ever use heartworm preventative on dogs who may be positive for heartworm disease. It is very, very bad for the dog.
Depending on where you live, there are other types of worms that our feline friends can be infected with.
Cats can get infected with whipworms, lungworms, and stomach worms. These are all much rarer than the other worms earlier in the article.
They’re still nasty, though.
Adult whipworms are about 1/4 of an inch long and live in the large intestines of infected cats. Whipworms can live in the environment anywhere from a few months to a few years! Their eggs can contaminate soil, food, water, feces, and animal flesh.
Symptoms of Whipworms:
Causes
Cats usually contract whipworms by ingesting infected matter, although transmission from an infected animal is possible. Whipworm infection in cats is not usually a serious issue.
Your vet can diagnose whipworms by testing a stool sample, although you may get many negative fecal tests before finding whipworm eggs.
Treatment for Whipworms in Cats:
Stomach worms inhabit the stomach, obviously. There are two basic types: Ollanulus tricuspis and Physaloptera species that infect cats.
The most common type is Ollanulu tricuspis and it spread between cats via vomiting and ingesting infected vomit.
Symptoms of stomach worms:
The diagnosis of stomach worms relies on detecting parasitic larva in vomit. Meaning you have to take the vomit to your veterinarian to examine.
The other type of stomach worm is the Physaloptera species of parasites. These worms are quite rare, actually. These worms cause the same symptoms as O. tricuspis does. Adult female worms attach to the stomach lining. Their eggs are passed out through feces and ingested by an intermediate host, such as a cricket or roach. Cats become infected by ingesting infected insects or eating rodents who have eaten infected insects. Confusing! In any case, diagnosis requires seeing the worm in vomit or detecting eggs in stool samples. Or a vet can insert a tube and perform a gastroscopy, which is examining the lining of the stomach with a small camera.
Stomach worms do not cause disease in humans.
Treatment for Stomach Worms:
You can help prevent stomach worms by keeping your pets indoors to limit hunting and make sure they don’t eat each other’s vomit.
There are many different species of lungworm and they each infect different types of animals. Cats, in particular, get infected by Aelurostrongylus abstrusus or Capillaria aerophila. These fun parasites can be 1-4 cm in length and look like hair.
Causes:
Cats become infected when they ingest an infected bird or mouse or by drinking contaminated water.
Diagnosis is done by a veterinarian via chest X-ray, fecal exam, microscopic examination of respiratory fluid or a complete blood count (CBC).
Symptoms of lungworm:
Treatments for lungworm:
It is important to note that lungworm infections can be a pain in the butt to treat. Their life cycle (inside the cat) means that every 7-14 days eggs could be hatching into larva, larva growing into adults, etc.
Cats can NOT be infected with pinworms, which is a human parasite that children often get. Pinworm infections are not caused by your dog or cat. Pinworm infections are often easily treatable with the same active ingredient that we give cats, pyrental pamoate.
You may have noticed that I did not list diatomaceous earth under any treatments for worms.
No, diatomaceous earth does not kill internal parasites. There have been multiple studies on DE and not one has shown it is effective against worms.
Diatomaceous earth does work as an environmental insecticide. It apparently is not very effective for killing slugs or snails, despite the rumors. It DOES discourage slugs and snails.
But here’s the problem: DE must come into direct contact with insects and it’s not 100%. The more you use and the longer you leave it, the better it works. It’s not hugely effective, but it DOES work.
If you pour a bunch of DE on roundworms that came out in a cat’s vomit or tapeworm segments, it will likely kill them.
No scientific evidence exists it is effective against parasites inside a host. There are many studies that have been done on DE and livestock and most of them show little to no difference between treated and untreated livestock.
Let’s face it, there is no proof that DE has any health benefits at all for people, cats, or livestock. The only thing studies have proven is it is not toxic or harmful to ingest.
Plus, we know:
So what happens when you ingest (or your cat ingests) DE? It gets WET. It STAYS wet. DE is not very effective wet. It has to be dry to work. Kind of impossible in your intestines.
Another important fact to consider is it takes a very long time for DE to kill insects. One dose of DE to kill internal parasites would never be effective. It would have to come into DIRECT contact with the worm or larva and it has to do so in enough quantity. That means multiple doses for a long period of time (like forever) to keep worms in check. If it worked when wet, which is does not.
Diatomaceous earth works by scratching the exoskeleton and causing dehydration. Let’s say it did work when wet, then how the heck would it cause dehydration inside the VERY wet environment of your cat’s stomach or intestines? Can’t dehydrate a parasite if it is literally living in a wet environment.
There IS a theory that actually might work regarding treating pasture of farm animals with DE to kill parasites and their larva BEFORE they infect the cows. The theory is if you treat the ground, you kill eggs and larva forms. There is not enough evidence this works though.
Don’t take my word for it, there are many studies regarding farm animals and DE. The most comprehensive list of livestock studies I’ve found can be read here.
I think the reason so many people think DE works on their cats is that they seem to think no symptoms equals no worms. Unless you take the cat’s feces into the vet on multiple occasions to study parasite egg loads, you will never know for certain if the cat has worms or not. Lack of symptoms does not equal no parasites.
Another thing to consider is that natural substances are never going to work as well as formulations created specifically for a purpose. Man utilizes nature in medicine all the time. They study what exactly makes a natural product effective and then synthesize it or concentrate it. Thus medicine and chemicals (many of which come from nature!) are always going to work better than natural products.
I don’t know about you, but parasites can be dangerous to kittens and cats, and I would rather use something that is proven to be effective, not something that ‘may or may not’ be.
The only thing I use DE for is for environment flea control in the barn, and only inside the barn. Diatomaceous earth kills beneficial insects too, including honey bees and ladybugs! So the idea of DE being natural and thus safe for the environment is a myth. Though, that said, it stops being effective while wet so a good rain washes it away.
I have a set deworming routine for my resident cats, my pets, my fosters, and my ferals. If you have pet cats, remember to speak to your veterinarian for their advice on the type of medication and how often you should give it.
For more finicky cats, these are also favorite dewormers of mine that combine ingredients:
If you’re a feral cat caretaker or a kitten foster, then you likely have your own worming routine and preferred medications. I would love for you to share your preferences with me below!
Lovies!
Disclaimer: I am not a veterinarian. Please consult your veterinarian for all medical diagnoses or treatment options, when possible. This post is to be used for informational purposes only.
This post was last modified on September 11, 2020 3:48 pm
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Hello Rochelle, thanks for sharing this live-saving article that can help out cats a lot. My little girl has been a victim of hookworms on several occasions and she just doesn't stop going around digging holes which I have noticed is the cause of the hookworm in her. I personally don't like seeing her sick. I have made use of the Pyrental Pamoate and it's worked really well. I will just try having it around in cases of such health issues.
Hi! Cats can get hookworms simply by walking on the ground if there are other animals defecating in the area so digging isn't the cause of it at all, though it definitely doesn't help if she's digging up some other cat's poo. Thanks for stopping by!
Indeed! Worms are really dangerous to the well-being of cats. They should be checked and also all efforts should be focused on deworming the cats. What I have read here proves that the infestation might be fatal for cats. Well, I didn't know about all these before and I do allow my cats to go out once a while. Wow! Thanks for sharing this as I would be more careful in the future.
Indoor cats too can get worms, remember. But it's less often than cats who go outside, definitely. Thanks for stopping by!
That's a lot of species of worms pets can get - and I never knew half of them since I've always referred to them collectively as 'worms,' without much thought. It seems like a few of these parasites (like the tapeworm) is something that can affect people as well, as you pointed out. And the adverse effects tapeworms alone can have are scary - I've seen a few documentaries and it's not something neither I nor any pet would want to deal with. They are parasites, through and through.
Thanks for visiting! Yeah, it's pretty scary when you see those documentaries! Luckily, most infestations aren't QUITE that bad, but it can still be yucky if we end up catching them from our pets if we didn't take proper care of them!
I have 3 indoor cats, so I didn't think we had to worry so much about worms. Thanks to this article, I will be bringing them to the vet ASAP. I did not know that there were so many worms to worry about. Do you think that I need to purchase a product for worms now, or should I wait for the vet visit?
Hi! Thanks for the question. It is always best to see a veterinarian if you have any concerns that your cats have worms. If you take your cats into the vet every year for annual vaccinations, they often deworm your cats at that time for roundworms and hookworms. If your cats are indoor-only, that might be all the deworming your beloved kitties need!
However, if you have had a flea problem, I would definitely deworm for tapeworms, just in case. As for anything else, definitely bring them into the vet if they start displaying problems such as diarrhea or you see worms. You may need a different type of deworming medication that the usual yearly one.
Though if it is a big concern for you, speak to your vet about deworming more often. The veterinarian will be able to tell you what types of worms are most common in your area and how often you should deworm them.
I have several extremely feral kitties i am feeding. "Untouchable" I have tried panacur in the food & they won't touch it. Any suggestions?
Hi, Kristie,
Unfortunately, Panacur is VERY nasty to cats. I have yet to get a cat to eat it in food. You can try the dog version of it, which comes in a powder, it might be much easier to put in their food. Though if you feed a LOT of cats, that's going to get more expensive than the goat or cow version of the medication.
Panacur only covers two parasites that other medications do not: whipworms and giardia. There are other medications you can try for other types of worms. If it's roundworms or hookworms, I'd stick to pyrental. And tapeworms, of course, do best on a different medication anyway.
Hope that helps! Wish there were another way to get ferals to eat Panacur. It sucks. If you're able to get the cats to ingest the dog Panacur in the food, let me know! I'd be interested to see if it works!
Hello Rochelle,
I love your site! Well done!
I have seven feral cats that I take care of. This morning, I saw two round worms in the vomit left by one of my outdoor cats. First time this has happened, so it prompted me to go on line to find an affordable dewormer for a colony of cats. I found you and then the site sent me to a product called Drontal, which is horribly expensive, but you recommended it for feral cats, because it could be crushed and sprinkled on the food, and it takes care of three types of worms. Here are my questions:
*In applying Drontal, or any other crushed pills in this way, how do I know if each cat is getting the recommended dose? Would applying it this way provide enough medication to do the trick?
*Is there another pill, or medication in powdered form, that I could sprinkle on the food that would be more affordable and more appetizing to the cats? Many people have stated that the pills are very bitter. My ferals are fussy when it comes to change.
Other than applying a crushed form of medication to the dry food, I don’t see how I can realistically treat my kitties for worms. Two of my cats allow me to pet them, but the other five, at this time, do not. Can you suggest any other product that would work for my situation and that won’t cost me $500? I’m grateful for any suggestions/information that you can give me.
Thank you for your help!
Hi, Chris!
Luckily, almost all deworming medications for cats have a HUGE safety margin. Meaning even if they accidentally eat more than their dose, they won't get sick. But the problem is making sure they actually DO eat it. If there is some way of separating their feeding so that each cat eats their own food would be best. But unfortunately with ferals, that can be a problem.
What I would do is use half of a small can of stinky wet food (or one of those meat tubes like Churu or you can find Squeeze Ups at your local Walmart) and prepare the bowls inside. Then when you come out, feed each cat at the same time and a few feet away from each other, if possible. And try to monitor it so that the fast eaters aren't pushing the slower eaters out of the way to finish their food, even if you have to add more food to the faster eater's bowls to keep them away from the drugged food. Does that make sense? That's how I used to do it before I could handle all of mine.
As for Drontal. Yes, it's expensive because it's actually a LOT of doses in the bottle. And you're absolutely right, it tastes AWFUL to cats. I personally only use Drontal when I give it orally, not in food because many cats who are well-fed won't eat drugged food, especially drugged with Drontal. My suggestion is to use liquid pyrental pamoate if you're sure it's roundworms. (As you said they were in vomit, I am very inclined to believe you. The only visible worms you can see in vomit would be roundworms (common) or tapeworms (very uncommon to find in vomit).)
Drontal contains pyrental pamoate (roundworms and hookworms) and a tapeworm medication called praziquantel. Tapeworm medications are really only needed if you notice tapeworm segments in feces or coming out the rear of a cat or you have a flea problem. So by purchasing liquid pyrental pamoate, you will have better luck hiding it in food. It's a yellow liquid medication and you can find it at any vet if you ask for a dewormer for ferals, and you already take your cats there, they will likely sell dewormer for kittens by the ounce. Or Amazon. AND it won't cost a ton of money! Pyrental pamoate is very cheap, requires one dose every 2 weeks for 2 or 3 doses and roundworms are gone.
Until they get infected again, of course. So I'd just set up a regular monthly deworming schedule with pyrental as roundworms are the most common worms cats get.
Another suggestion is to see if you can hide Drontal in those Greenie Pill Pockets for cats. But... that can be a crapshoot. Sometimes it won't work at all, sometimes it works, but only once, and some cats just swallow anything nummy.
Hope that helps!
Hello hello! I'm living beside a cat colony of around 25, they appear to have all been desexed, and they are fed by well meaning volunteers each night who are only giving them milk and no water. I am going to purchase a 3.5litre watering device for them and would like to de-flea & de-worm them, but I am on an incredibly tight budget and can't really spend more that $30 a month. Since they are all being fed, and some are local housecats, it's difficult to know which cats to dose/help etc, since they all appear to be a relatively healthy weight. Do you have any advice on how to group-wise limit fleas&worms? Maybe through crushed items in food?
Hi, Lena,
Uh, they are only giving milk? That's... not good. Cats are mostly lactose intolerant. That's got to give them gas, diarrhea, or even cramps. Thank you for thinking of water for them! Adding wet food can also help them stay hydrated, btw. Cats can absolutely get their moisture from food too.
Let's talk about worm medications first that you can put in food. The most common worms cats suffer are roundworms and hookworms and they can easily be dewormed every month with pyrantel pamoate in their food. It's fairly cheap as one 16 oz bottle can last for like a HUNDREDS of cat doses. It's dosed by weight, 0.1 ml per pound of cat. So an average cat can get 1 ml of pyrantel pamoate per 10 pounds of cat. AND even if they eat more than they should of the drugged food, it's a REALLY safe medication if the cat is accidentally eating too much of it. And it's not that nasty in food, so most cats seem to not mind it in their wet food.
Now, pyrantel pamoate won't take care of tapeworms. There's one OTC medication for tapeworms and that is praziquantel and you can find it alone or combined with pyrantel pamoate in a medication called Drontal. This medication is more expensive AND it's harder to hide in food. When it is crushed up, it's pretty bitter. I'm uncertain you'd be able to get them to eat it in food. I have YET to get a cat to eat Drontal mixed in food. The regular praziquantel, only one cat ate the drugged food and he's not that picky. LOL. I would only worry about tapeworms if you SEE tapeworm segments near their anus.
Now for fleas. There are only like TWO medications that can be put in food to kill adult fleas for cats. The first is Capstar, which only lasts for 24 hours. Very effective for fleas for that 24 hours though and can be hidden in food crushed up and isn't awful tasting, but picky cats will still ignore drugged food sometimes. Some vet professionals will use Capstar in combination with a medication called lufenuron, which prevents fleas from reaching adulthood, basically. Lufenuron is a monthly oral medication as well and it's really cheap, wherever you find it.
The only other oral flea medication for cats, is called Comfortis, but it's a prescription medication. It does last a month though.
But other than those meds, most other cat meds are topical, not oral.
Hope that helps!