AIM: To analyze the occurrence and clinical characteristics of adverse drug reactions (ADR) induced by four programmed cell death protein 1 (PD-1) inhibitors according to literature reports, and to provide reference for clinical safe medication. METHODS: PubMed, CNKI, and Wanfang, and other databases were searched to collect case reports of adverse reactions caused by four PD-1 inhibitors, including camrelizumab, sintilimab, toripalimab, and tislelizumab. RESULTS: A total of 105 eligible literature reports were retrieved from the databases at home and abroad (as of June 1, 2022), including 42 reports on camrelizumab with 47 patients, 29 reports on sintilimab with 30 patients, 21 reports on toripalimab with 24 patients and 13 reports on tislelizumab with 15 patients. Among them, there were 76 males (65.5%) and 40 females (34.5%), with a gender ratio of 1.9:1.0. The age range was between 29 to 84 years old, and the onset of ADR mainly occurred within 4 months after the first use of PD-1 inhibitors. Immune-related adverse reactions were mainly manifested as skin and its attachment (41 cases, 34.5%), endocrine system (25 cases, 21.0%), and cardiovascular system (22 cases, 18.5%). Most patients improved after symptomatic and?supportive?treatment. CONCLUSION: Immune-related adverse effects (irAEs) may occur at any time during treatment with the four PD-1 inhibitors, among these the skin system is most frequently affected, followed by the cardiovascular and endocrine systems. This suggests the importance of individualized drug administration and stringent control over indications in clinical practice. Close monitoring throughout immunotherapy is essential to minimize or prevent irAEs, thus ensuring patient safety in medication usage.