Traditional Chinese medicine and pharmacology is a very important field of knowledge.
Various kinds of drugs, when combined, some can become good medicine, and others may turn into unknown poisons. When Ye Feng entrusted his friends from the Valley of the Medicine God to establish the Divine Doctor Sect, he particularly emphasized the four characters "physician's benevolent heart," insisting that they must not be misused.
Just as Ye Feng said, Xu Tiefeng's illness was really not a troublesome matter to deal with. He merely had blockages in the Eight Extraordinary Meridians within his body, which led to a disruption of Qi-Blood circulation and eventually triggered an old, latent ailment, leaving him bedridden now.
Yu Feiyu didn't dare to refuse, nor could she refuse.