Introduction. Polypharmacy in elderly patients causes the development of undesirable side reactions. Deprescribing is an effective method of dealing with polypharmacy. Purpose of the study. Study of the relationship between polypharmacy and the development of adverse reactions in elderly patients. To evaluate the effectiveness of deprescribing in elderly patients. Materials and methods. The study included 148 elderly polio-morbid patients aged 66 to 89 years (mean age 74.9 years) who were analyzed for the number of drugs taken. The patients of the sample were questioned using the questionnaire developed by us for the presence of undesirable side reactions, with subsequent analysis of the side reactions indicated in the questionnaire. Using the Naranjo algorithm, a causal relationship between the drugs taken and the development of adverse reactions was determined. An assessment of the risk of negative effects of drugs taken on the body of elderly patients was carried out, undesirable side reactions caused by taking drugs, with their subsequent cancellation, were identified. Results. An assessment of the risk of negative effects of drugs taken on the body of elderly patients was carried out, undesirable side reactions caused by taking drugs, with their subsequent cancellation, were identified. As a result of the deprescribing, the number of adverse reactions significantly decreased. There were no negative effects from discontinuation of drugs in patients. Conclusions. Deprescribing is an effective method of dealing with polypharmacy. The results of our study showed that drug withdrawal is possible in the conditions of outpatient care in primary health care, and is safe for patients. Reducing the drug load on the patient reduces the number of unwanted side reactions.