Objective: To establish a method of the determination of content of total alkaloids in the small pinellia added in the Poria cocos soup. Method: The absorbance of total alkaloids was measured by UV spectrophotometer after visualization with bromothymol blue

and the max detection wavelength was set at 414 nm

the concentration of total alkaloids was linear in the range of 2.2-7.7 mg ·L-1(correlation coefficient r =0.999 8)

and its average recovery and correlation coefficient r were 97.38% and 0.999 8. Result: The content of alkaloids in compound prescription decoctum was 0.057 22%

disassembled prescription decoctum was 0.023 25% and simple prescriptions decoctum was 0.008 47%. Conclusion: The method established was simple

sensitive

accurate and with good repetition

which can be suited for the quality control of total alkaloids in the small pinellia added in the Poria cocos soup.