Cats

Fenbendazole for Cats — Uses, Dosage & Safety

Last updated June 19, 2026

Fenbendazole is used in cats to treat several intestinal and respiratory parasites. Some feline uses are off-label, so veterinary guidance on dose and duration is especially valuable.

On this page What it treats Dosing & course Safety When to call your vet

What fenbendazole treats in cats

In cats, fenbendazole is commonly used against:

Roundworms (Toxocara cati)
Hookworms
Lungworms (Aelurostrongylus)
Certain tapeworms (Taenia species)
Giardia in some cases

As with dogs, it is not the right tool for the flea tapeworm (Dipylidium).

Dosing and the treatment course

Several feline uses of fenbendazole are off-label, meaning a veterinarian directs the dose and length of treatment based on the parasite involved. A multi-day course is typical, and lungworm or Giardia protocols may run longer than a routine deworming.

Always follow the label. The figures above describe common label guidance, not a prescription. Exact dosing depends on the specific product's concentration and your animal's weight. When in doubt, your veterinarian can confirm the right amount and schedule.

A note on off-label use

"Off-label" is normal and common in feline medicine — many safe, effective treatments in cats fall into this category. It simply means the product wasn't formally registered for that exact use in cats, so the dose comes from veterinary judgement rather than the package. That's why a quick conversation with your vet matters more here than for some other species.

Is it safe?

Fenbendazole has a wide margin of safety in cats when used as directed, and serious reactions are uncommon. Mild, temporary digestive upset is the most frequently reported effect. Read the full safety and side-effect guide before treating, especially for pregnant, nursing, very young, or unwell animals.

When to call your veterinarian

Book a visit or call if your animal is very young or pregnant, has another illness, is on other medication, isn't improving after treatment, or shows anything beyond brief, mild stomach upset. A simple fecal test is the best way to confirm which parasite you're dealing with and whether it has cleared.