Yin and yang are both deficient, so yin and yang will be replenished at the same time, and medicines that replenish yin and yang will appear at the same time.

For those with only yin deficiency, according to "Those who are good at replenishing yin must seek yin from yang, then yin will win over yang and the spring will be endless;"

Those with only yang deficiency , according to "Those who are good at nourishing yang must seek yang from yin, then yang will be assisted by yin and the biochemical process will be endless;"

So there will be drugs that tonify yin and yang at the same time.