Objective To investigate the characteristics and rules of adverse drug reaction (ADR) caused by anti-tumor drugs, and to provide reference for the safe use of anti-tumor drugs in clinical practice.Methods The ADR reports of anti-tumor drugs reported to the National Adverse Drug Reaction Monitoring System in our hospital from January 1, 2021 to December 31, 2022 were collected. The types of ADR reports, gender and age of patients, route of administration, occurrence time of ADR, types of drugs, tumor status of patients, ADR-involved system/organ and clinical manifestations, outcome, association evaluation, occupation of reporter were retrospectively analyzed, and the factors affecting the severity of ADR were correlated.Results Among the 857 ADR reports, 627 cases (73.16%) were serious ADRs, 230 cases (26.84%) were general ADRs. There were no new ADRs. The tumor stage of the patients and the type of drugs used significantly affected the severity of ADR (P<0.05). Among the ADR reports, there were 421 male cases (49.12%) and 436 female cases (50.88%). Patients aged from 45 to 59 accounted for the highest proportion (49.36%). Intravenous administration was the main route of administration that causes ADR (96.62%). ADR mostly occurred at 1 to 7 days after medication (30.69%), and the occurrence time varied depending on the type of drug and its toxic manifestations. Cytotoxic drugs were the most likely type of drugs to cause ADR, among which platinum metals accounted for the highest proportion (38.97%). Lung cancer patients made the highest incidence of ADR. The most common system/organ involved in ADR was the hematological system (63.35%). 95.10% of the patients with ADR recovered or were improved after treatment. The ADR correlation evaluation showed 70.36% of cases were very likely correlated with the drug. Doctors (73.63%) were the main group who reported ADRs in the system.Conclusion Anti-tumor drugs, particularly cytotoxic agents, are associated with a high incidence and severity of ADRs. Clinical practice should enhance targeted monitoring for high-risk patient groups, critical drugs, and serious ADRs. It is suggested that clinical pharmacists prioritize patient medication education and pharmaceutical care in routine practice to facilitate rational use of antitumor drugs in clinical settings.