Drug profile

The FDA adverse-event record for Vitamin B12

661 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Vitamin B12. See the species affected, top reactions, and outcomes below.

661
adverse-event reports
23.1%
death-coded share
Cat
most-reported species
134
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.
661
Total Reports
153
Deaths Reported
23.1%
Death Rate

Active Ingredients

Vitamin B12

Administration Routes

UnknownSubcutaneousParenteralOralIntravenousOtherIntramuscularCutaneousOphthalmicIntraocular

Species Affected

Cat 322
Dog 320
Human 13
Pig 3
Cattle 2
Horse 1

Most Affected Breeds

Domestic Shorthair 184
Retriever - Labrador 42
Domestic Mediumhair 34
Shepherd Dog - German 28
Domestic Longhair 25
Chihuahua 21
Unknown 13
Siamese 13
Cat (unknown) 12
Retriever - Golden 11

Most Reported Reactions

Vomiting 134
Lethargy (see also Central nervous system depression in 'Neurological') 103
Diarrhoea 101
Weight loss 96
Anorexia 88
Death by euthanasia 86
Other abnormal test result NOS 73
Not eating 69
Lethargy (see also Central nervous system depression in Neurological) 67
Lack of efficacy - NOS 66
Death 60
Ataxia 57

Outcome Breakdown

Ongoing
259 (38.7%)
Outcome Unknown
142 (21.2%)
Recovered/Normal
105 (15.7%)
Euthanized
87 (13.0%)
Died
68 (10.2%)
Recovered with Sequela
8 (1.2%)

Vitamin B12 Adverse Event Insights

661 reports name Vitamin B12; 153 recorded a death outcome (23.1% of reported events, not a population-level mortality rate). Active ingredient: Vitamin B12. Administration routes: Unknown, Subcutaneous, Parenteral, Oral.

By species: Cat (322 reports), Dog (320 reports), Human (13 reports). By breed: Domestic Shorthair (184), Retriever - Labrador (42), Domestic Mediumhair (34).

Leading clinical signs: Vomiting (134), Lethargy (see also Central nervous system depression in 'Neurological') (103), Diarrhoea (101), Weight loss (96). Outcome, 669 coded reports: Ongoing leads at 38.7%.

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.