Doctrine of Signatures


The Doctrine of Signatures is an ancient belief whose origin is lost in the mists of time. It purports that certain physical attributes of a plant indicate its therapeutic value — attributes including colour, shape, texture and even smell.

  • Eyebright, with its flower looking like a bloodshot eye is good for eyesight.
  • The yellow latex of celandine is good for liver problems (where the telltale yellow skin of jaundice is a major symptom giveaway).
  • Walnut halves and ginkgo leaves look spookily like a human brain. Walnuts contain melatonin and mega amounts of omega three fatty acids, both excellent for brain function. Ginkgo helps improve memory and cognition.

Pliny the Elder, Dioscorides, Paracelsus and Nicolas Culpepper were among the physicians who believed in the Doctrine of Signatures. From the 1700’s on, the concept was ridiculed. Researchers and apologists now believe that at most the doctrine was a mnemonic, or learning aid for physicians to learn their material medica. The actions of the plants were known well before it was noticed that there was a physical similarity to the illness or body part.

Regardless of its veracity, the romantic notion that comes from the Hermetic literature that “God has endowed each herb, each stone, each star, and each sign with a ‘secret’ which, when it becomes known to man, will be of utility”, is a seductive one.