mentha is a plant native to the mediterranean region and is cultivated throughout the world due to its use in different areas. mentha spicata, mentha piperita, and mentha pulegium are among the most important aromatic plants of this genus. recent studies have shown that the essential oils of these plants contain components that are active in the oral cavity due to their antibacterial, antifungal, and anti-inflammatory activities. however, the composition of these essential oils can be modified by environmental factors such as light, precipitation, the growing site, and soil, which might directly influence their activities. the purpose of this study is to physically and chemically characterize the different commercial essential oils of mint: spearmint, peppermint, and pennyroyal in order to determine their quality. these essential oils were collected from different regions in morocco. the quality of the essential oils was determined by organoleptic properties and analysis of their constituents using thin layer chromatographic (tlc) technique. the results showed variations in the composition of some major components of these essential oils.