A passage from Medicinal Plants of the American Southwest:
Aristolochia watsonii, at least according to one chemical analysis, contains low amounts of toxic AA1 and AA2, but higher amounts of low–toxicity AA3. This may seem like good news, but the problem that occurs with relying upon just one analysis is the same problem that is encountered when just one study or one sample is relied upon: the chance of one stand–alone observation being inaccurate is much greater than a number of independent, yet similar in conclusion, observations being inaccurate. So until more research is available on A. watsonii’s chemistry, I suggest using Aristolochia watsonii, and indeed all other species of Aristolochia, only externally.
