Oat (Avena sativa) is a light-green annual grass with a bushy root. Since oat is a dietary fiber, it influences the regularity of bowel movement. Oat is often used for disorders of the gastrointestinal tract, gallbladder, kidney, and cardiovascular systems. It is used for constipation, diarrhea, rheumatism, throat and chest complaints, fatigue, hypertension, lowering uric acid levels, and in tonics. Oat is said to have sedative, and diuretic effects.