Thiamine mononitrate is a form of Vitamin B1. Vitamin B1 is important in the breakdown of carbohydrates from foods into products needed by the body. Thiamine is found in foods such as cereals, whole grains, meat, nuts, beans, and peas. Thiamine mononitrate is added to certain foods to maintain nutrient content during processing. It is also used to treat or prevent vitamin B1 deficiency, beriberi, and inflammation of the nerves associated with pellagra or pregnancy. Thiamine is available as a dietary supplement in various forms, including thiamine mononitrate and thiamine hydrochloride.