The goal of the study was to test the biological activities of Peppermint oil (Mentha spicata L.) extracted from leaves of Peppermint plant in growth of yeast Candida albicans isolated from the feces of 100 patients suffering from symptoms of Irritable bowel syndrome (IBS), and find out the relationship with demographic characteristics. The data and specimen have been collected for the period from 1st November 2011 to the end of February 2012, from Teaching Baghdad Hospital "Laboratory Central", chosen randomly according to the sample specifications from 11 years to 50 years. The study revealed potential inhibitory activity of peppermint oil against yeast, Candida albicans in vitro, and showed that the mean of age was (33.5) years, and most of them are women, living in urban. Gas chromatographic analysis revealed the presence of 31 volatile compounds in shoot, two of these compounds, Menthol and Terpinene were identified as terpenoids.