Chemical compounds in plants mediate their effects on the human body through processes identical to those already well understood for the chemical compounds in conventional drugs; thus herbal medicines do not differ greatly from conventional drugs in terms of how they work. This enables herbal medicines to be as effective as conventional medicines, but also gives them the same potential to cause harmful side effects.
^ Vogl, S; Picker, P; Mihaly-Bison, J; Fakhrudin, N; Atanasov, AG; Heiss, EH; Wawrosch, C; Reznicek, G; Dirsch, VM; Saukel, J; Kopp, B (2013). "Ethnopharmacological in vitro studies on Austria's folk medicine - An unexplored lore in vitro anti-inflammatory activities of 71 Austrian traditional herbal drugs". J Ethnopharmacol. 149 (3): 750–71. doi:10.1016/j.jep.2013.06.007. PMC 3791396. PMID 23770053.
Another well know spice in the kitchen cinnamon is also known for it's medicinal properties. While not really an herb I still think it's important to list it in our list of herbs and their uses. Cinnamon actually comes from the inner bark of a tree in the laurel family. It's been used for centuries and was a hot commodity for trade in ancient times. In fact during the first century A.D. in Rome cinnamon was 15 times more expensive than silver. The Chinese were probably the first to use cinnamon as a medicinal herb and used it to treat fevers, and diarrhea. In more modern times cinnamon has been found to stabilize blood sugar levels in diabetics, as it has an insulin kind of effect.