OBJECTIVE： To investigate the efficacy difference of gypsum in oral and external prescriptions， so as to provide reference for safe and effective drug use in clinic. METHODS： According to Chinese Medical Classics （electronic books） and Selected Dictionary of Chinese Medical Prescriptions， the prescriptions containing gypsum from the Eastern Han Dynasty to the Modern Times （up to 1979） were summarized； the regularity of clinical use of gypsum by physicians in past dynasties were analyzed. RESULTS： A total of 682 prescriptions containing gypsum were collected. According to the time， there were 169 prescriptions of the Song Dynasty （24.8％） and 152 prescriptions of the Qing Dynasty （22.3％）； there were 138 prescriptions of the Ming Dynasty （20.2％） and 118 prescriptions of the Modern Times （up to 1979， 17.3％）； there were 53 prescriptions of the Jin and Yuan Dynasty （7.8％） and 52 prescriptions of the Han Dynasty， the Jin Dynasty， Northern and Southern Dynasties， and Tang Dynasty （7.6％）. Gypsum mainly showed the efficacy of clearing heat-fire， relieving restlessness and slaking thirst， promoting wound healing and tissue regeneration， astringing dampness and stopping bleeding， etc. Among them， there were 516 prescriptions of clearing heat-fire （75.7％）， 69 prescriptions of relieving restlessness and slaking thirst （10.1％）， 56 prescriptions of promoting wound healing and tissue regeneration （8.2％）， 20 prescriptions of astringing dampness and stopping bleeding （2.9％）， 21 prescriptions of other efficacy （tooth fixation， cosmetology， health care and so on， 3.1％）. This indicated that the effect of gypsum was mainly clearing heat-fire； gypsum could treat heat-induced disease by combining with other drugs. It could be used in following prescriptions， such as yangming heat syndrome， syndrome of flaring heat in Qifen and Xuefen （Ying）， Qifen fever complicated with syndrome of deficiency of Qi and Yin， other meridians complicated with excess-heat syndrome， miscellaneous dosease due to internal injury. In addition， gypsum could be cyed erally or externally， and it can be taken orally after being calcined. CONCLUSIONS： By studying the prescriptions of gypsum used by physicians in past dynasties， it can promote the further use of gypsum， and give better play its clinical efficacy.