Why are physicians so wary of herbal remedies?

Evidence or Lack Of. As pediatrician, I worry about herbal remedies mostly because of lack of convincing research that they are effective and safe. If I have proof of safety, trying it will not hurt. Often it is assumed that "natural" products are safe. If so, then those mushrooms growing in the backyard will not poison me. Seriously, most pediatric herbal cures, when studied have so far been found not to work well.
Complicated. Several issues: 1. Many patients do not inform us of what they are taking and they can affect the prescription medicine you are taking. 2. Herbal medicine is not regulated by the fda so you can not guarantee the dosing is always accurate. 3. Since the fda has no oversight, the companies making the medicine can make any claims about the remedy, whether it is accurate or not.