Fast and dynamic development of medicine and pharmacy is linked not only with efficacy and safety of drugs but also with their cost–effectiveness, especially when patients’ co-payment systematically increases. OBJECTIVES: To investigate the recognition of the term “pharmacoeconomics” by patients of an open pharmacy and the role of economic aspects in decision making concerning drug purchases. METHODS: A total of 270 patients (170 suffering from chronic and 100 from acute diseases) were interviewed (18 questions with a 5 level weighted / validity scale). RESULTS: A total of 67% of respondents were able to define (more or less precisely) the term “pharmacoeconomics”. Thirty percent (30%) of patients treated acutely and eight 8% chronically were unable to pay for their prescriptions (level of co-payment too high), which decreases their compliance (different factors also apply). Price elasticity of demand was low: 67 out of 100 treated chronically and 76 out of 100 treated acutely would not have a prescription made up if the price of a drug increased by 50%. On the other hand, 88% and 92% of patients treated for chronic and acute diseases respectively would find sources of finance if non-treatment led to serious health consequences and 93% of respondents would pay more for a drug if they were sure it was absolutely safe. Forty percent (40%) of respondents declared that they would like to use only drugs which make them able to work, 81% prefer to take effective but sometimes expensive drugs in order to shorten hospitalization time. CONCLUSIONS: Elements of cost-effectiveness, relationship between the price of a drug and its effectiveness and safety as well as different cost components linked to a medical condition remain within the scope of interest of patients purchasing drugs in pharmacy.