Abstract: To explore the suitable drying methods for Rheum tanguticumMaxim.exBalf.bycolor,drying time,drying rate and content of active ingredients as indexes.The results showed that:with the water loss of R.tanguticum,drying process,physical activity and physical form and the active ingredient content also changed significant.Different drying methods have a great impact on the quality of R.tanguticum.Combination these indicators with equipment requirements and suitability for large-scale promotion and other aspects into account,the suitable drying method for R.tanguticum is recommended to dryin the shade,or sun-drying or oven-drying at constant 45-55 ℃.

Key words: Rheum tanguticumMaxim.exBalf, drying methods, anthraquinone derivatives, sennoside, tannin