PD-1/PD-L1 (programmed cell death 1/programmed cell death 1 ligand 1) and CTLA-4 (cytotoxic T lymphocyte antigen 4) are currently approved major immune checkpoints. Immune checkpoint inhibitors against them are novel monoclonal antibodies that perform well in a variety of malignancies such as melanoma, renal cell carcinoma, non-small-cell lung cancer, urothelial carcinoma and Hodgkin′s lymphoma. However, with the increasing use of immune checkpoint inhibitors, immune-related adverse events cannot be ignored. The incidence of gastrointestinal toxicity is second only to skin toxicity. In this review, we focused on the mechanisms of these immune checkpoint inhibitors and the characteristics of gastrointestinal toxicity induced by them, and also discussed the clinical management strategies.