Context: Self-medication is the use of unprescribed drugs; this means that people obtain drugs on their own initiative and without the assistance of health professionals. This is an increasingly common practice among the population that can cause numerous problems, becoming a public health problem. Aims: To determine the patterns of self-medication in customers who frequented a community pharmacy in the city of Antofagasta. Methods: A survey was conducted to 297 users over 18 years and with adequate mental and communicative power to answer the questions, and attending the pharmacy to buy a drug without a prescription. Results: The study revealed that of the 297 people who practiced self-medication, 41% do it with a frequency of at least once a month. The woman practiced in 64% and the men in 36%. The range of age of the studied group was between 31-50 years. The main reason to practice the self medication was to recognize symptoms (33%), within the most notable was the headache (11%). The therapeutic group of the most requested medicines was the NSAIDs (20%), and of them the paracetamol was the most used. Conclusions: The results reveal that a high percentage of customers surveyed self-medicate, which shows this practice as a real problem, so it is necessary to educate people.