Herbal medicine is comprised of wood, animals, insects, grains, plants, fruit... etc. Of all the Herbal medicines one of the ingredient is mineral including: natural copper, naenatite, scaleitum serpentinum, succinum; there are only a handful mineral ingredients.
Sulfur which is poisonous, is fed to ducks and then duck meat or egg is consumed to indirectly absorb sulfur to treat ailments. Outside of that, plants containing poison called pinellia, aconote, Korean aconium, cnidium, dry Chinese lacquer... etc are poison scrubbed before usage.
For example, viper's poison is very good for treating ailments but, we do not use the poison directly. The viper is killed and maggot is cultivated on the dead viper's body and then the maggot is fed to the chicken. Finally the chicken is used for medicine.
The rest is herbal ingredients that is not poisonous even if consumed directly. To explain just what is herbal medicine, the East Sea of Korea produces dry whiting which is used to treat poisoning from briquet gas, ingestion of toxic chemicals, fire burn, alcohol poisoning, and its effects are immediate. After overdrinking, Korean wives immediately make dry whiting soup, and even in the case of blackouts, conscience comes back after drinking dry whiting soup. When thermal burns are received, the burned areas become smooth from "fire toxic" and tingling and burning sensation are felt; if dry whiting soup is consumed, "fire toxic" disappears, appetite returns, and cucumber smelling burnet is applied and the pain subsides. Coal briquette fired floors were/are used in some countries and the poisoning from briguet gas, if warmth of the chest is still there, the victim could survive by consuming dry whiting soup.
Analyzation by modern science cannot find any evidence of poison being eliminated by dry whiting composition. Even if modern science cannot find the ingredient/composition of the dry whiting that makes a alcohol induced blacked out person, it still works to give conscience back to an alcohol induced blacked out person. . Dry whiting must be of the 'East Sea of Korea', otherwise it does not work. Before we had drugs to exterminate parasites, if there were parasites in the stomach, consumption of pomegranate bark eliminated roundworm would have eliminated the parasites but, people did not use them. Even suffocated victims (if there is still warmth/soul) could be revived by obtaining blood from the hen's comb and dropped onto the mouth. Just what connection does blood from hen's comb have to do with reviving a suffocation victim?
Unless Tao is reached, the answer will never be revealed. Herbal medicine ingredients that humans cannot directly consume could be fed to duck, pig, dog, chicken, black goat and then be used as ingredients for medicine.