Dispelling the pathogens and strengthening Yang-Qi are two distinct yet complementary methods of treatment. Strengthening healthy Yang-Qi, or nourishing therapy, treats deficiency syndromes. Eliminating pathogens or purging treats excess syndromes. Different pathogens respond to different therapies. For example, diaphoresis dispels pathogens from the body’s exterior, emetics alleviate phlegm accumulation, food retention, or food poisoning, and purging is used when intestinal wastes get knotted up with pathogenic heat, etc.
When vital functions are weakened and pathogens dominate, pathogens can be driven out without injuring Yang-Qi. Strengthening body resistance and dispelling pathogens may be done simultaneously, but only after determining whether the main problem is weakened body resistance or strengthened pathogens. If pathogens dominate, dispelling them is emphasized. However, when Yang-Qi is seriously compromised, it should be strengthened. In cases of uterine bleeding due to blood stasis, for instance, if blood stasis is not removed, uterine bleeding will continue. Thus, it is necessary to promote blood circulation and eliminate blood stasis first by strengthening the Yang-Qi.
The general condition must be improved first when pathogens dominate and healthy Qi is extremely weak. In this case, tonics are first given to improve the general condition, and then extremely potent herbs can drive out pathogens. If the order were reversed, the patient would be further weakened. For parasitic infections, for example, it is advisable to strengthen the Spleen-Yang first to improve body resistance, and then eliminate the parasites, because the healthy Qi is too weak to endure the side effects of the anti-parasitic.