RESUMO
Herb pair， a common form of compounding in Chinese medicinal prescriptions， reflects the experience of pharmacists in clinical medication in the past. It is characterized by simple composition while has the basic characteristics of Chinese medicine compounding. The combination of two medicinal herbs can enhance effect or reduce toxicity. Coptidis Rhizoma （CR） has the effects of clearing heat， drying dampness， purging fire， and removing toxin. Euodiae Fructus （EF） is acrid， bitter， and hot-natured， which can not only warm the Yang Qi in spleen and stomach to dissipate cold and relieve pain， but also descend stomach Qi and prevent vomiting. Furthermore， it can warm the liver and kidney. CR and EF form a typical cold-heat herb pair， which oppose and yet also complement each other. Specifically， their cold and heat natures interact with each other to clear liver fire， harmonize stomach for descending adverse Qi， relieve depression， and dissipate mass. CR clears the intestine and stops dysentery， while EF warms the middle and promotes the circulation of Qi. The combination of them can thus clear heat， dry dampness， and relieve pain. Modern pharmacological studies have demonstrated that CR-EF has not only significant efficacy against digestive system diseases but also good anti-cancer， anti-inflammatory， anti-ulcer， and lipid-lowering activities. Therefore， the article summarized the effect enhancement and toxicity reduction of the herb pair at the levels of cellular molecule， isolated organ， and whole animal， and clarified the mechanism of its pharmacological action. It will provide a theoretical basis for further development and clinical use of the herb pair.