The damage of gastrointestinal tract caused by drugs is a common occurence. This type of injury can be caused by numerous medications. The clinical manifestation of these damages may vary from benign injury to severe complications such as bleeding or perforation of the intestine. Esophageal injury is most commonly presented with esophagitis, where inflammatory changes, erosions and ulcers whose depth may vary can be detected endoscopically. There is a particular predisposition to drug damage in people with motility disorder, cardiomegaly, and mechanical obstruction, eg. esophageal stenosis or tumor. Drugs that damage the stomach lead to reactive gastropathy, erosions, ulcers and perforation. Drugs that damage the stomach the most are nonsteroidal antiinflammatory drugs due to their wide but also long-term applications. However, many other drugs have an effect on the gastric mucosa. Adverse drug effects usually occur on small and large intestine. The symptoms of small intestine damage are often mild and nonspecific, but the challenges associated with examining the small intestine make it difficult to diagnose. At the same time numerous drugs are associated with colon damage and the mechanisms of damage are different either by changing the normal flora and inducing infection, or leading to thrombosis and ischemia. The aim of this review is to present and summarize the current knowledge of the effects of certain drugs on the gastrointestinal system and to show their clinical, endoscopic and histological features.