Is Cephalexin (Keflex) Safe for Dogs?
Why it’s a problem
Cephalexin is a common antibiotic with low toxicity, and veterinary versions are actually prescribed for dogs. The trouble with human pills is the dose: a dog that gets into a bottle can swallow many capsules, leading to vomiting, diarrhea, and appetite loss. Very large ingestions can cause dehydration from ongoing GI upset.
How to keep your pet safe
Store Keflex and other antibiotics away from dogs, since capsule bottles are easy to chew open. Never self-dose — your vet should confirm the infection and prescribe the correct course.
Warning signs to watch for
Drooling, nausea, vomiting, diarrhea, loss of appetite, mild belly discomfort; large ingestions may cause repeated vomiting and lethargy.
When to call the vet
Call your vet or a pet poison hotline with an estimate of how many capsules were eaten. Home monitoring is often enough, but persistent vomiting needs an exam.
Common questions
My dog ate a handful of Keflex capsules — is that an emergency?
Cephalexin has low toxicity, but a handful of capsules can cause significant vomiting and diarrhea. Call your vet or a poison hotline with the amount swallowed to decide on monitoring versus a visit.
Isn’t cephalexin actually a dog antibiotic?
Yes, vets prescribe it often, but at doses calculated for the individual dog. Human capsules should never be dosed out at home.
When would my dog need to be seen after eating cephalexin?
If vomiting repeats, your dog refuses food and water, or seems weak and uncomfortable, an exam is warranted. Otherwise your vet may just advise watching for a day.
More medications hazards for dogs
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).