Episodes can last for hours or days as well as alternating with fairly symptom-free periods of time. When something interferes with the protective mechanisms of the tummy, a series of issues can occur from mild acid indigestion to harmful bleeding ulcers. Gastritis is an umbrella term for one of the most common troubles, swelling of the belly lining. For functional dyspepsia-- "average" indigestion-- treatment and also prevention are the same.