In this review the authors focus on the adverse GIT events during long-term treatment with non-steroid anti-inflammatory drugs, and explain pathogenesis of the NSA induced gastropathy and enteropathy. The risk groups of patients and prophylactic and therapeutic modalities are discussed. There are indices that most of the NSA gastric ulcers don't induce clinical symptoms, and massive bleeding may be the first clinical manifestation. This is why the clinical symptoms cannot be used as predictors of NSA gastropathy. It seems, on the author's clinical experience, that more than half cases of massive non-variceal bleeding from upper GIT is induced by non-steroid anti-inflammatory drugs and acetylsalicylic acid. NSA-gastropathy often presents with multifocal ulcers and erosions in the antrum of the stomach. The course of massive bleeding induced by NSA is associated with high rate of lethality.