On Prof. Yin Huihe's "Modified Mah Xing Shi Gan Tang"

Mah Xing Shi Gan Tang is a formula from the Shanghan Lun for treating Taiyang warm disease. It consists of Mahuang (ephedra), Xingren (apricot kernel), Shigao (gypsum), and Gancao (licorice), hence its name. Zhang Zhongjing described its indication as "sweating with panting." Later generations use it for body heat, urgent panting, thirst, and a rapid pulse caused by wind-cold transforming to heat, or by wind-heat, or by exuberant lung heat. The formula may be used whether there is sweating or not.

On the basis of Mah Xing Shi Gan Tang, Prof. Yin Huihe added Sangbaipi (morus root bark) and Tinglizi (descurainia seed) to form his "modified Mah Xing Shi Gan Tang," composed of: Mahuang 9 g, Xingren 9 g, raw Gancao 6 g, raw Shigao 30 g (decocted first), Sangbaipi 12 g, Tinglizi 9 g. Method: decoct in water; one dose daily, taken in two divided doses.

Prof. Yin noted that his modified Mah Xing Shi Gan Tang is intended for cough and wheezing without phlegm, or with little phlegm, accompanied by wheezing rattling in the throat. Its main indications are: cough and wheezing due to lung heat with phlegm sounds in the throat, little phlegm that is hard to expectorate; wheezing asthma with inability to lie flat and little phlegm; high fever with slight chills, chest fullness, thirst, a thin white or yellow coating, a floating rapid pulse, and in severe cases noisy breathing.

It may be used for what modern medicine calls bronchial asthma, acute pneumonia, pneumonia complicating measles, lobar pneumonia, and high fever of the exuberant lung-heat type. Beyond that, this formula can also treat allergic rhinitis and allergic dermatitis of the exuberant lung-heat type.

What surprises me about this formula is that Prof. Yin described it for a phlegm-free condition, yet in fact, judging from its composition, it is better suited to cases with phlegm or pleural effusion presenting the pattern of exuberant lung heat. Patients with exuberant lung heat who pant, gasp, fever, and have abundant phlegm—even pleural effusion and white lung—can all be treated with this formula, and it works well.

Mah Xing Shi Gan Tang clears and drains lung heat to treat the root, while Sangbaipi and Tinglizi promote urination and reduce swelling to treat the branch; combining root and branch makes the effect more evident. The Tinglizi Dazao Xiefei Tang in the Jingui Yaolue uses only two herbs—Tinglizi and jujube—and drains the lung to calm wheezing, promote urination, and reduce swelling. Sangbaipi has the same action of draining the lung to calm wheezing and promoting urination to reduce swelling. So adding Tinglizi and Sangbaipi gives this formula the action of treating pleural effusion.

Then can this formula be used to treat pleural effusion in cancer patients? Yes, provided the patient shows the "exuberant lung heat" pattern. Of course, for cancer patients such a formula alone is not enough; corresponding anti-tumor drugs must be used at the same time. Especially in malignant pleural effusion, without anti-tumor treatment the effusion may ease temporarily but will soon recur.