Gastroade Extra is for the prevention of stomach ulcers in horses, also known as Equine Gastric Ulcer Syndrome or EGUS. Each tube of GASTROADE XTRA contains 2.28g of Omeprazole. There are 4 doses in each tube. Omeprazole works against the production of acid in the stomach. It is the same ingredient in Prilosec OTC® (made by AstraZeneca) used for gastric ulcers in humans. Horses produce stomach acids 24 hours a day. Acid released in an empty stomach is thought to be the main cause of EGUS. The stomach in a horse requires continuous roughage which produces saliva that together act as a buffer to protect the mucosal lining from the continuous production of acid. When a horse is fed twice a day and is on a strenuous training/competition schedule, much of the day is spent NOT eating, therefore the stomach is left without any buffer against the continuous acid production resulting in the development of EGUS. Bismuth Subsalicylate gives almost instant relief of the discomfort and pain associated with EGUS by coating the stomach lining to protect it against stomach acid.