Herbs and other medicinal plants are used in various ways (teas, lotions, creams, syrups, inhalants) as support for physical ailments. Their own biological agents interact with the client's immune system and so help the healing process.
Shamanically, herbs have animals associated with them, most commonly insects. These insects are the bearer of the knowledge about the medicinal effects of the plant, and help the shaman use it the appropriate way.
These objects are the long term "pills" in a shaman's repertoire of healing applications. Due to their molecular structures, they harmonize any energy force they come in contact with, just as the quartz crystals in watches harmonize the battery's raw energy and transform it into steady impulses. There is a crystal for each ailment, as each ailment is considered an unharmonious energy that needs to be equalized.
Crystals work slowly, but with long term effects.
A shaman also associates spirits with each crystal, that helps him/her with finding the right application for the client's needs.