On September 29, 2026, the FDA announced it had issued a warning letter to Neogen, following an investigation that linked a Neogen’s Hycoat product “to serious infections and deaths in horses.” The FDA stated the “incident involved at least 20 horse deaths, making it the largest number of horse deaths ever associated with a quality defect in an FDA-regulated veterinary medical product and the most deaths of any animal species linked to microbiological contamination of an FDA-regulated product labeled as sterile. The FDA also reviewed Hycoat’s labeling and determined that the product is also misbranded “because its labeling fails to bear adequate directions for use.”

On this news, Neogen stock fell $0.99 or 7.22%, to close at $12.73 on September 29, 2026.