Disturbances of the hind gut/large intestine definitely exist but the correct treatment is to find the cause and correct it. “Hind gut ulcers” is not a real disease, says Eleanor Kellon, VMD. In her opinion, there is no such thing as “hindgut ulcer syndrome” that is a correlate of gastric ulcer syndrome, and certainly no cause that a supplement would correctly treat.
Source: Horse Network, March 4, 2016. (direct link unavailable)
It is not unusual today to hear people claiming 60%-65% of horses have hind gut ulcers. However, if you read medicine, surgery and pathology textbooks or other published literature there is no mention of this widespread “hindgut ulcer disease.” It isn’t even mentioned in the horse health articles for owners on AAEP.org.