Recurrent colic, tooth grinding, poor appetite, hair coat, and performance may indicate an ulcer. Many horses with ulcers do not display clear symptoms.

Ulcers must be diagnosed by a gastroscopy. Horses must refrain from eating for 12 to 18 hours and refrain from drinking for 2 to 3 hours prior to the procedure. The veterinarian then may examine the horse’s stomach lining to check for any ulcers.