Neogen received warning letters from the Food and Drug Administration following an investigation that linked a vet wound care product labeled as sterile to serious infections and deaths in horses.
The investigation looked at Neogen Vet Hycoat in relation to at least 20 reported horse deaths. Neogen initiated a voluntary recall of the product in late January.
The incident is the largest number of horse deaths ever associated with a quality defect in an FDA-regulated vet medical product, the FDA said Tuesday.
Neogen shares declined 3.6% to $13.21.
The FDA received reports starting in late 2025 from vets who used Hycoat as an injection. Although the product's label describes it as sterile, the FDA's testing found contamination with multiple fungi.
Injecting a fungus-contaminated solution poses a significant risk to the animal, including infection, tissue destruction and system illness, the FDA said.
Nearly 100 horses developed serious joint infections following administration of Hycoat, and at least 20 horses were euthanized after unsuccessful treatment of the infections.
Hycoat is marketed by Neogen as a vet device and is labeled as a sterile topical wound management solution intended for use on surgical wounds, burns and similar conditions. It is packaged in a glass vial with a septum top.
The FDA said its investigation revealed serious violations, including the manufacture of products labeled as sterile in a facility with unsanitary conditions.
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