Colloidal bismuth subcitrate (CBS) is very effective in the treatment of gastroduodenal disorders and appears to act via several mechanisms. It has little acid-neutralizing effect and does not affect acid secretion. It is uncertain whether CBS affects pepsin secretion, but it does inhibit peptic activity. It causes an increase in mucus glycoprotein secretion and may also bind to the gastric mucus layer to act as a diffusion barrier to HCl. CBS accelerates ulcer healing and causes an accumulation of epidermal growth factor around the ulcer. In addition, it has a cytoprotective effect and increases mucosal secretion of prostaglandins and bicarbonate. CBS has bactericidal effects against Helicobacter pylori (which is associated with gastritis and peptic ulcers). It also prevents adhesion of H. pylori to epithelial cells and can inhibit enzymes secreted by H. pylori, such as proteases, lipases, glycosidases, and phospholipases.