Introduction: Due to the frequency and variety of the Medicinal herbs in Fars province, this study aimed to study the rate and reasons for medical herb use by the patients visiting the health centers in Fars Province.Material and Methods: This study, carried out in the health centers of Fars province, used a twostage cluster sampling of 2100. A researcher made questionnaire was used to collect the data. The questionnaire included 7 demographic and 31 expert questions. The data were analyzed using SPSS 22, spearman correlation coefficient, Friedman's and chi-square. Statistical significance was considered to be p<0.05.Results: The use of herbal medicine by the woman was statistically significant compared to the men. There was a significant correlation between location, employment status, insurance status, the average of monthly income and the consumption of medical herbs (p<0.05). As the Spearman Correlation coefficient (0.73) shows, there was a positive correlation between the beliefs and information about medical herbs and the consumption rate. The use of herbal medicine used for the treatment of skin, respiratory, urinary tract, endocrine system diseases was 30 %, 21 %, 20 %, 18.5% and 10% respectively. Liquorice, Thyme, Borage and Four seeds were the mostly used herbal medicines. The most reported side effects of the use of medicinal herbs were pain in the stomach, nausea and vomiting and skin reactions respectively. Sixty nine percent of the patients preferred the herbal medicines and 31% preferred drugs at the time of their illness.Conclusion: As the findings of this study show, people prefer using herbal medicine to chemical ones especially in the treatment of skin diseases. Thus, it is necessary to give people correct information and control health conditions of herbal medicines.