Peppermint (Mentha piperita L.) is an aromatic and medicinal plant that has high Menthol content. This medicinal plant is often used in tea and for flavouring ice cream, confectionery, chewing gum and toothpaste. In order to evaluation the impacts of drying methods on drying time and qualitative characteristics of peppermint, an experiment was conducted at the Special Laboratory, College of Agriculture, Ferdowsi University of Mashhad during 2012 based on completely randomized design with six replications. Leaves dried at three temperature with oven (30, 40 and 60ᵒC) and natural methods (shaded and sunny airs). The drying process was continued until the moisture content of leaves reduced about 10% based on dry weight. The results showed that the effect of different drying methods was significant (p≤0.01) on essential oil and Menthol contents of peppermint. By increasing in oven temperature was declined drying time for leaves. The highest essential oil and Menthol contents were observed in shaded air (with 3.1 and 64.1%, respectively) and their lowest were for 60ᵒC oven (with 1.5 and 21.1%, respectively).

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