Doctrine of Signatures

The doctrine of signatures is a philosophy shared by herbalists from the time of Dioscurides and Galen. This doctrine states that herbs that resemble various parts of the body can be used to treat ailments of that part of the body. Examples include the plants liverwort; snakeroot, an antidote for snake venom; lungwort; bloodroot; toothwort; and wormwood, to expel intestinal parasites. A theological justification was made for this philosophy: "It was reasoned that the Almighty must have set his sign upon the various means of curing disease which he provided." The concept is still reflected in the common names of some plants whose shapes and colors reminded herbalists of the parts of the body where they were thought to do good. Scientists see the doctrine of signatures as superstition. There is no scientific evidence that plant shapes and colors help in the discovery of medical uses of plants. In similar doctrines from India, the sage Agasthiar is supposed to have had the capability to converse with plants to thus obtain from the plants which ailments and diseases they, the plants, could ameliorate and even cure.