Consumption of feedstuffs contaminated by Fusarium mycotoxins and the development of equine gastric ulcer syndrome (EGUS) affect the overall health of horses. A study was conducted to determine if feed-borne mycotoxins have an effect on EGUS, and the efficacy of a glucomannan mycotoxin adsorbent (GMA) was determined. Feed intake was decreased with the GMA diet compared to control horses. Body weight, ulcer score and gastrin concentration were unaffected by diet. Some significant changes in blood parameters potentially indicate liver damage and inhibition of protein synthesis. Histological evaluation showed an increase in mononuclear cells in the glandular region of the contaminated group likely indicating signs of gastritis. The incorporation of the GMA may reduce these negative effects on the horse based on our findings. It can be concluded that horses are susceptible to Fusarium mycotoxins with a possible effect on EGUS, as seen in the cells of the gastric glandular mucosa. / Alltech Inc., Nicholasville, Kentucky and OMAFRA