Deworming a cat requires a veterinarian’s diagnosis, the correct medication for the specific parasite, and follow-up doses timed to the cat’s age and lifestyle.
For the full breakdown, see our best Dewormer for Cats and Dogs guide.
The real answer to how to deworm cats comes down to three things: identifying the worm type, using the right drug at the right dose, and repeating treatment on a schedule that matches your cat’s risk. Skip any of those three and the worms usually return, or the treatment simply doesn’t work. WebMD’s veterinary guide on cat deworming emphasizes that a fecal exam before treatment is the safest first step.
When Should You Deworm Your Cat?
The deworming schedule depends entirely on the cat’s age and exposure risk. Kittens need early, frequent treatment because they can contract roundworms from their mother’s milk. Most veterinary sources recommend starting at 2 to 3 weeks of age and repeating every 2 weeks until 9 weeks old, then continuing monthly until 6 months.
Adult cats follow a less aggressive schedule. Low-risk indoor cats generally need deworming twice a year, while outdoor cats, hunting cats, or those on raw diets typically require treatment every 3 months. The higher the exposure to fleas, rodents, or soil where other animals defecate, the more frequent the deworming should be.
| Cat Profile | Recommended Frequency | Key Reason |
|---|---|---|
| Kittens (under 6 months) | Every 2 weeks to 9 weeks, then monthly to 6 months | Roundworms from mother’s milk; immature immune system |
| Indoor adult (low risk) | Twice per year | Minimal parasite exposure |
| Outdoor or hunting adult | Every 3 months | Regular contact with rodents, soil, and fleas |
| Cat on a raw diet | Every 3 months | Raw meat can carry tapeworm larvae |
| Multi-cat household with outdoor access | Every 3 months for all cats | Cross-infection raises overall risk |
The Step-by-Step Deworming Process
1. See a veterinarian first. A fecal exam identifies the specific worm type. Roundworms and tapeworms are the most common intestinal parasites in cats, but they require different medications. Guessing the wrong type means the treatment fails.
2. Use the correct product for that parasite. Broad-spectrum over-the-counter dewormers may not cover all worm types. Your veterinarian will prescribe the right drug in the right form — oral tablet, liquid suspension, or topical spot-on treatment.
3. Dose by weight, not by age. Underdosing leaves some worms alive, and overdosing can cause side effects. Weigh the cat accurately and follow the dosage instructions to the letter.
4. Administer the medication as directed. Oral tablets can be hidden in a small amount of wet food or given with a pill syringe. Topical products go on the skin at the base of the neck or between the shoulder blades — not on the fur — and the cat should be kept from grooming the area until the product dries.
5. Repeat follow-up doses if prescribed. Many protocols require a second dose 2 to 3 weeks later to catch newly hatched worms that survived the first treatment in a resistant larval stage. Skipping this follow-up is the most common reason deworming fails.
6. If one cat goes outdoors and brings worms back, indoor-only cats can pick them up through shared litter boxes or grooming. Our roundup of the best dewormers for cats and dogs compares the top products by worm type and ease of use to help you choose.
Preventing Reinfection After Deworming
Killing the worms already inside the cat is only half the job. The environment must be cleaned to stop the cat from swallowing new eggs or larvae right after treatment.
Scoop litter boxes daily and disinfect them weekly with hot water and bleach. Wash the cat’s bedding in hot water, and vacuum carpets and furniture where flea eggs or worm eggs may have settled. Fleas are a common carrier of tapeworms, so consistent flea control is a critical part of worm prevention.
Remove feces from the yard or garden promptly, especially if children play in the area. Some cat parasites can infect humans, so wearing gloves during cleanup and washing hands afterward protects the whole household.
FAQs
Can you buy dewormer for cats without a vet prescription?
Some dewormers are sold over the counter at pet stores and online, but veterinary guidance is strongly recommended. A fecal exam confirms which worm type is present, and OTC products may not cover tapeworms or hookworms. Using the wrong product wastes money and leaves the cat infected.
How do I know if my cat has worms?
Common signs include visible worm segments in the stool or around the anus (tapeworm segments look like grains of rice), a potbellied appearance, weight loss despite a normal appetite, scooting, and occasional vomiting. A veterinarian can confirm the diagnosis with a simple fecal flotation test.
Can humans get worms from their cats?
Yes, some cat intestinal parasites are zoonotic. Roundworms and hookworms pose the highest risk, especially to children who may contact contaminated soil or litter. Washing hands after handling litter, wearing gloves for garden cleanup, and keeping the cat on a regular deworming schedule greatly reduce household risk.
References & Sources
- WebMD. “How to Deworm Kittens and Cats.” Covers diagnosis, treatment guidance, and preventive care for cat deworming.
- Virbac. “How Often Should You Deworm Your Cat?” Details frequency schedules by age and lifestyle risk factors.
- Dartmouth Veterinary Hospital. “Deworming.” Professional veterinary guidance on safe deworming protocols.