People have taken the advantage of using herbs as an effective method for medical treatment since long times ago that can be attributed for their cheap prices and the belief of their being safer than equivalent chemical medicines. Industrial development and the ever-increasing exposure of environmental threatening materials especially heavy metals have merged the necessity for iterative examination of herbal products safety. In this study, highly sensitive and selective method of Differential Pulse Stripping Voltammetry was employed to measure copper, lead and cadmium in seven herbal syrups available in Tehran city drug stores. The mean concentrations of lead, cooper and cadmium were measured to be 5.95μg/L, 6.269 μg/L, 66.926ng/L in the studied samples, respectively. The results indicate that the extent of copper, lead and cadmium amounts were below the standards of WHO for all the samples.