Horsemint is a herb with stem from 40 to 120 cm in height. Leaves are oblong-elliptical to lanceolate. Flowers are purplish or white about 3-5 mm long. Mentha longifolia is a folk remedy and have been used as a traditional medicine in Iran and other countries. Studies have shown pharmacological and therapeutic effects of the plant. It has various pharmacological properties such as gastrointestinal, antimicrobial and nervous system effects. The pharmacological effects is due to the presence of pulegone followed by menthone, menthol, isomenthone, borneol, 8-cineole and piperitenone. Furthermore, the dose exerts toxic effects in different systems of the body.