Chai Hu (Rx. Bupleurum) is a great herb for a variety of viral issues as well as stress-induced problems. Interferon therapy is designed to address viral issues as well. The interaction of Chai Hu (Rx. Bupleurum) and interferon is an additive problem. Interferon therapy boosts the strength and sensitivity of the immune system. Chai Hu (Rx. Bupleurum) has the same (but weaker) effect. When these two medicines are used together, they can give rise to an excessive immune response that damages the lungs.
Formulas containing Chai Hu (Rx. Bupleurum) are very popular in Japan in the treatment of Hepatitis C, but periodically interferon therapy is used for the same problem. When patients catch a cold, the immune system responds. But if interferon and Chai Hu (Rx. Bupleurum) are being taken together, we have seen cases in which the immune system will over react. This causes damage to the lungs and has led to some deaths in Japan.
Chai Hu (Rx. Bupleurum) has not been shown to injure the lung tissues, but may over stimulate the neutrophils to release granulocytes elastase and oxygen radicals, which subsequently damage lung tissue. The ﬁbroblasts that repair the damaged tissue may increase the risk of pulmonary ﬁbrosis. [Source]
Bottom line is, if you’re getting interferon therapy, avoid taking Chai Hu (Rx. Bupleurum) formulas by twice the amount of time between your injection appointments. If you get an injection twice a week, wait a week. If you get an injection once a week, wait two weeks. For more, please consult with a physician or licensed healthcare professional who has more than a passing understanding of Chinese herbs.