Is Cephalexin (Keflex) Safe for Cats?
Why it’s a problem
Cephalexin is used in veterinary medicine too, so a single human capsule is more likely to cause stomach upset than organ damage in a cat. The bigger risks are a very large ingestion and a cat that stops eating afterward. Cats are also more prone to foamy drooling when nauseated by pills.
How to keep your pet safe
Keep antibiotic bottles off counters and out of drawers a cat cannot open, and never give human pills to a cat. Any feline antibiotic should come from your vet with a real diagnosis behind it.
Warning signs to watch for
Foamy drooling, vomiting, diarrhea, refusal to eat, hiding, low energy; heavy ingestions can cause dehydration and marked lethargy.
When to call the vet
Call your veterinarian or a pet poison hotline with the estimated amount eaten. If your cat will not eat within a day of the exposure, arrange an exam.
Common questions
My cat chewed one Keflex capsule — do I need the ER tonight?
One capsule usually causes only nausea in a healthy adult cat, so a call to your vet or a poison hotline is a reasonable first step. Kittens, elderly cats, or multiple capsules deserve faster attention.
My cat is foaming at the mouth after swallowing my pill — why?
Bitter-tasting drugs commonly trigger frothy drooling in cats. It is usually from nausea or taste rather than poisoning, but mention it when you call for advice.
Can I finish my own cephalexin course on my cat’s wound?
No. Doses, duration, and even the choice of antibiotic differ for cats, and wrong treatment can worsen or mask an infection. See your vet.
More medications hazards for cats
This page is general educational information, not a substitute for professional veterinary advice. Every pet is different — if your animal ate or touched something concerning, contact your veterinarian or a pet poison hotline right away. In the US: Pet Poison Helpline (855) 764-7661, ASPCA Animal Poison Control (888) 426-4435 (fees may apply).