Objective (s): HERBAL WATERS are extensively used in most parts of Iran including Mashhad. Visiting a patient with total blindness due to daily ingestion of around 200 ml of HERBAL water (Plant forty water) per day for six months was the rational for methanol determination in all HERBAL WATERS available in Mashhad markets.Materials and Methods: A total of two hundred and nineteen bottles of HERBAL WATERS were randomly bought from Mashhad market. Methanol concentration was determined by gas chromatography, using a Flame Ionized Detector. Benzene (1000 mg/l) was applied as the internal standard. Collected data was analyzed by SPSS software (version 11.5), using appropriate descriptive statistical tests.Results: Forty six different HERBAL WATERS from three main producing factories (A, B and C) were tested. Highest methanol concentration was measured in dill water of A (1208±202.74 mg/l), concentrated rose water of A (1017.41±59.68 mg/l) and concentrated rose water of B (978.52±92.81 mg/l). Lowest methanol concentration was determined in Trachyspermum copticum water of B (18.93±1.04 mg/l), cinnamon and ginger water of B (29.64±10.88 mg/l) and rice skin water of A (41.33±7.85 mg/l). Mean methanol concentrations of HERBAL WATERS including ginger, cinnamon, dill, peppermint, alfalfa, and plant forty from A, B and C were 374.69, 209.81 and 280.12 mg/l, respectively (P<0.001).Conclusion: Methanol concentration in all HERBAL WATERS, especially rose water of the three producers was very high that may induce toxicity in people taking these products regularly for a long time.