The article is devoted to the study of problems arising in proving and establishing a causal relationship between adverse reactions to medicines and harm to the health of patients in the framework of the civil process. The work includes an analysis of complex medical disputes, where special attention is paid to the influence of drugs not only as causes of iatrogenic torts, but also the concomitant effect of adverse drug reactions. The authors provide examples of thalidomide tragedy, adverse outcomes in drug confusion and evidentiary issues. The specifics of registration of generics, the difficulty of identifying adverse drug reactions that mimic the symptoms of common diseases, and the legal obligations of medical and pharmaceutical professionals to report such cases in a timely manner complement the review of problems. Judicial practice, real cases are demonstrated, showing how the lack of clear evidentiary criteria complicates the process of establishing guilt and protecting medical organizations and individual specialists. Based on the analysis, the authors conclude that it is necessary to improve the existing procedures for proving and strengthening pharmacovigilance mechanisms in order to timely identify and prevent adverse drug reactions.