Background & Aim: Herbal medicine usage is prevalent among world people from a long time ago and, It has been five times from 90th to 97th in the USA. According to increasing usage of herbal drugs and investigating the knowledge, beliefs and function of patients to herbal drugs, this research was done. Experimental: It is a descriptive, cross sectional study which carried on 30 patients who referred to one of the clinic centers that researchers have referred to this center and have filled out questionnaires that consist of demographic and knowledge, beliefs, and function of patients to herbal medicines. Then data analyzed with SPSS version 15. Results and discussion: Range of woman age was 19-47 y/o with mean 30±8 and rang age of men was 22-50 y/o with mean 27.4±12. About 23.3% are under diploma, 63.3% are diploma and higher, 10% are graduate and higher. The results show that 63.3% of patients had knowledge about herbal medicines and 93.3% of them expressed that recognize special herbal medicines for some disease. Also, 73.3% expressed that herbal medicine use is safe and 96.7% believed herbal medicines. About 30% of them believed that medicinal herbs must be bought from pharmacy. In addition, 93.3% expressed that medicinal herbs use is not limited to Iran. The most prevalent herbs respectively are: thyme (63.3%), borage (56.6%), mint juice (36.6%), four seeds (23.33%), Fumitory juice (20%), camels-thorn juice, green tea, London rocket seeds (16.6%), and lavender (13.33%). The most cause of herbal medicine use is stomach illness, sweating, common cold, relaxing, kidney stones and menstrual disorders. Industrial and practical recommendations: Because 93.3% of the patient referring to clinics used herbal drugs and regarded them safe, giving useful and comprehensive information about herbal drugs and increasing the knowledge of herbalists to prevent from medicinal introduction in order to boost the awareness, belief and function of patients and finally their heath, is so necessary. پرونده مقاله