Drug profile

The FDA adverse-event record for Cephalexin

2,713 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Cephalexin. See the species affected, top reactions, and outcomes below.

2,713
adverse-event reports
9.4%
death-coded share
Dog
most-reported species
744
Vomiting - top reaction
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Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
2,713
Total Reports
255
Deaths Reported
9.4%
Death Rate

Active Ingredients

Cephalexin

Administration Routes

OralUnknownTopicalSubcutaneousOtherOphthalmicParenteralIntravenous

Species Affected

Dog 2,537
Unknown 86
Cat 85
Human 3
Ferret 2

Most Affected Breeds

Retriever - Labrador 398
Shepherd Dog - German 161
Retriever - Golden 131
Crossbred Canine/dog 107
Pit Bull 104
Unknown 90
Boxer (German Boxer) 89
Terrier - Bull - American Pit 89
Bulldog 84
Dog (unknown) 54

Most Reported Reactions

Vomiting 744
Emesis 372
Lethargy (see also Central nervous system depression in 'Neurological') 367
Overdose 220
Diarrhoea 215
Other abnormal test result NOS 206
Accidental exposure 206
Lack of efficacy - NOS 170
Anorexia 168
Seizure NOS 132
Death by euthanasia 131
Weight loss 117

Outcome Breakdown

Recovered/Normal
964 (36.7%)
Ongoing
758 (28.9%)
Outcome Unknown
574 (21.9%)
Euthanized
130 (4.9%)
Died
126 (4.8%)
Recovered with Sequela
75 (2.9%)

Cephalexin Adverse Event Insights

2,713 reports name Cephalexin; 255 recorded a death outcome (9.4% of reported events, not a population-level mortality rate). Active ingredient: Cephalexin. Administration routes: Oral, Unknown, Topical, Subcutaneous.

By species: Dog (2,537 reports), Unknown (86 reports), Cat (85 reports). By breed: Retriever - Labrador (398), Shepherd Dog - German (161), Retriever - Golden (131).

Leading clinical signs: Vomiting (744), Emesis (372), Lethargy (see also Central nervous system depression in 'Neurological') (367), Overdose (220). Outcome, 2,627 coded reports: Recovered/Normal leads at 36.7%.

Read these counts as reporting volume, not risk: per our methodology, a widely-prescribed drug will rack up more raw FDA reports in a given year than a rarely-used one at an identical true rate, so we recommend comparing within similar-exposure products rather than across the full 2025 catalog.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

Every figure on PlainBreed is rendered directly from FDA openFDA adverse event data, no number is typed in by an editor. This page draws directly on FDA openFDA data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.