The gastrointestinal or digestive system facilitates the breakdown and digestion of food, absorption of nutrients, and excretion of waste products from the body. Common diseases include gastroesophageal reflux disease or GERD, peptic ulcers, diarrhea, constipation, hepatitis, and inflammatory bowel disease. Medications used to treat gastrointestinal disorders are among the most commonly prescribed drugs and include antacids, proton pump inhibitors, and laxatives.
Table showing common drug classes and examples of the gastrointestinal system
| Drug class | Generic name | Brand name(s) | Primary use |
| Antacids | Aluminium hydroxide, magnesium hydroxide, calcium carbonate | Amphojel, Milk of Magnesia, Tums, Rolaids | Neutralize gastric acidity |
| Proton pump inhibitors | Omeprazole, pantoprazole, esomeprazole | Prilosec, Protonix, Nexium | Decrease the production of gastric acid, peptic ulcers, and gastroesophageal reflux disease (GERD) |
| Histamine (H2) blockers | Ranitidine, famotidine | Zantac, Pepcid | Decrease the production of gastric acid, peptic ulcers, and gastroesophageal reflux disease (GERD) |
| Antidiarrheals | Loperamide, Bismuth subsalicylate | Imodium A-D, Lomotil, Pepto-Bismol | Treatment of diarrhea |
| Laxatives | Polyethylene glycol, docusate, psyllium, bisacodyl | MiraLAX, Colace, Metamucil, Dulcolax | Treatment of constipation |