Doctrine of signatures
![Eyebright was used for eye infections, from the supposed resemblance of the flower to an eye](/Images/godic/202501/09/Augentrost0827.jpg")
![Lungwort was thought to have the signature of the lungs and was used to treat lung infections.](/Images/godic/202501/09/Suffolk_lungwort0827.jpg")
The doctrine of signatures, dating from the time of Dioscurides and Galen, states that herbs that resemble various parts of the body can be used by herbalists to treat ailments of those parts of the body. A theological justification for this, as stated by botanists like William Coles, was that God would have wanted to show men what plants would be useful for.