OBJECTIVE:To optimize the extraction process for Sihuang paste.METHODS:The Radix et Rhizoma Rhei,Radix Scutellariae were extracted with ethanol,and the effects of the concentration and dosage of ethanol,and the ext-racting time,extraction times on the content of emodin were investigated by orthogonal experiment.The Rhizoma coptidis and Cortex Phellodendri were extracted by water decoction method,and the effects of amount of water,the soaking time,the decoction time and decoction times on the content of tannin were investigated by orthogonal experiment.RESULTS:The optimum alcohol extracting condition for Radix et Rhizoma Rhei,Radix Scutellaria was as follows:adding 60% alcohol at a dose of 6 times that of the total medicinal substances and extracting for 1 h/time for 3 times.The optimum water extracting condition for Rhizoma Coptidis and Cortex Phellodendri was as follows:soaking medicinal substances in water(with the ratio of medicinal substances to water at 1∶6)for 0.5 h,decocting for 2 h and extracting for 3 times.CONCLUSION:The optimized methods are simple and stable,which provide theoretic basis for industrial production.