Background: Herbal distillates had been used for many centuries as herbal medicine in Traditional Persian medicine. Recently, some studies claimed the presence of methanol in different types of herbal distillates which can cause different complications or even death as methanol is highly toxic. The main purpose of this study was to determine methanol content in the commonly-used industrial herbal distillates produced in Mashhad. 
Methods: A total of forty-five herbal water extracts of five types of most commonly used herbal distillates including peppermint, camel thorn, chicory, fumitory and rose water were randomly bought from market. Methanol content of each sample was measured according to the standard method.  Collected data was analyzed by SPSS software using appropriate descriptive statistical tests.
Results: The lowest and highest concentration of methanol were found in rose water extract (mean=9.04 ± 3.42 mg/dL) and peppermint extract (mean=93.87 ± 76.59 mg/dL) samples respectively. One-way ANOVA showed statistically significant differences between methanol concentration in the studied herbal distillates (P =0.03). 
Conclusion: Methanol concentration, especially in peppermint extract was very high that may induce toxicity in people taking these products regularly for a long time. Therefore, considering the harmful effects of methanol on human health, further studies are required for determining permitted levels of methanol in herbal distillates.