Self-medication has become an emerging phenomenon that increasingly threatens public health. The purpose of this study is to determine the prevalence of self-medication at Mostaganem (northern west Algeria), for this, a cross-sectional descriptive study based on the collection of data by questionnaire addressed to pharmacists and patients who self-medicate; during the year 2019.The results obtained shows that women are often self-medicate (61%) than men (39%) with a sex ratio of 0.65. The most consuming category (76%) is aged between 30 and 50 years and has a university level. Paracetamol is the highest analgesic used with (75%), but the risk incurred by the self-medication with aspirin which is higher than paracetamol, for this reason, it is clear to consider rules for the proper use of self-medication in consultation and at pharmacy to prevent health population risks.