Dental conditions such as toothache, gingival bleeding, discomfort and halitosis have been identified as common reasons for self-medication. Thus, the purpose of this study was to determine the mechanisms of the relationship between self-medication and knowledge of adverse reactions in a group of patients who were seen in the dental service of the Loreto regional hospital in 2022. After reviewing the background and theory, a cross-sectional observational study of causal-analytic scope was conducted. The study population consisted of 400 patients, randomly selected under probability sampling, and two structured questionnaires were applied to a sample of 197 patients. In order to verify the hypotheses, the respective Chi2 test of independence at 5% was used. The results showed that 81.2% of the patients lacked information about the negative consequences of drugs, while the tendency to self...