The Doctrine of Signatures theory has risen and fallen in popularity among cultures throughout the globe since ancient times, including a recent controversial upswing.
What if plants came with a certain clue or "signature" to help people know how to use them? Called the Doctrine of Signatures, this theory has risen and fallen in popularity among cultures throughout the globe since ancient times, including a recent controversial upswing.
The clues, often associated with specific body parts, can come in the form of a plant's texture, color, shape, smell, behavior, or environment. So, a mint species growing near water may help cure a "wet" illness such as a cold. Or a stomach-shaped ginger root may help nausea.
While they could be coincidence, many examples are validated by some studies. Brain-shaped walnuts help brain development. Worm-shaped purslane protects intestines from parasites. Carrots, whose cross-section resembles an eye, strengthens eyes. Womb-like avocados balance hormones and protect against cervical cancer. Multi-layered onions purify multi-layered skin.
Critics admit the signatures sometimes hold water, but also slam them as outdated, subjective, irresponsible, and "wildly dangerous" theories whose "rotting corpses must be buried to keep them from stinking up the place."
With 375,000 existing plant species and counting, one can see where the Doctrine may be problematic.