The purpose of the study is to draw the attention of the legal and medical community to the problem of insufficient awareness of the patient about the upcoming medical intervention; to identify the scope of interaction between the court and the expert in relation to disputes related to improper information. Despite the fact that the conclusion about improper informing of the patient implies a legal assessment of the circumstances, special medical knowledge is needed to identify some defects of voluntary informed consent. The expert, in particular, can answer the questions of the court about what risks are characteristic of a certain type of medical intervention (perforations, bleeding, etc.) and how high their probability was in relation to a particular patient (taking into account his state of health, anatomical features); whether there were alternative treatment options. Based on the explanations received, the court will be able to assess whether the patient’s attention was focused on the relevant circumstances, whether his consent was conscious, and the complications that occurred were foreseeable.