Drug profile

The FDA adverse-event record for Methylsulfonylmethane

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

13
adverse-event reports
7.7%
death-coded share
Dog
most-reported species
4
Lack of efficacy - NOS - 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.
13
Total Reports
1
Deaths Reported
7.7%
Death Rate

Active Ingredients

Methylsulfonylmethane

Administration Routes

UnknownOral

Species Affected

Dog 11
Horse 2

Most Affected Breeds

Pit Bull 2
Retriever - Labrador 2
Quarter Horse 2
Pug 1
Cattle Dog - Australian (blue heeler, red heeler, Queensland cattledog) 1
Dog (other) 1
Collie - Border 1
Crossbred Canine/dog 1
Terrier - Welsh 1
Retriever - Golden 1

Most Reported Reactions

Lack of efficacy - NOS 4
Vomiting 3
Falling 2
Walking difficulty 2
Respiratory signs 1
Death 1
Malaise 1
Urinary incontinence 1
Ataxia 1
Overdose 1
Jaw disorder 1
Chattering of teeth 1

Outcome Breakdown

Outcome Unknown
6 (46.2%)
Recovered/Normal
3 (23.1%)
Ongoing
3 (23.1%)
Died
1 (7.7%)

Methylsulfonylmethane Adverse Event Insights

13 reports name Methylsulfonylmethane; 1 recorded a death outcome (7.7% of reported events, not a population-level mortality rate). Active ingredient: Methylsulfonylmethane. Administration routes: Unknown, Oral.

By species: Dog (11 reports), Horse (2 reports). By breed: Pit Bull (2), Retriever - Labrador (2), Quarter Horse (2).

Leading clinical signs: Lack of efficacy - NOS (4), Vomiting (3), Falling (2), Walking difficulty (2). Outcome, 13 coded reports: Outcome Unknown leads at 46.2%.

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.