Sympathetic magic, also known as imitative magic, is a type of magic based on imitation or correspondence.
It has been said that the theory of sympathetic magic was first developed by Sir James George Frazer in The Golden Bough (1889); Richard Andree, however, anticipates Frazer, writing of 'Sympathie-Zauber' in his 1878 Ethnographische Parallelen und Vergleiche. Frazer further subcategorised sympathetic magic into two varieties: that relying on similarity, and that relying on contact or 'contagion':
If we analyze the principles of thought on which magic is based, they will probably be found to resolve themselves into two: first, that like produces like, or that an effect resembles its cause; and, second, that things which have once been in contact with each other continue to act on each other at a distance after the physical contact has been severed. The former principle may be called the Law of Similarity, the latter the Law of Contact or Contagion. From the first of these principles, namely the Law of Similarity, the magician infers that he can produce any effect he desires merely by imitating it: from the second he infers that whatever he does to a material object will affect equally the person with whom the object was once in contact, whether it formed part of his body or not.
Imitation involves using effigies, fetishes or poppets to affect the environment of people, or occasionally people themselves. Voodoo dolls are an example of fetishes used in this way. Such as using a lock of hair on the doll creating a "link" between the doll and the person the hair came from so whatever happens to the doll will also happen on the person.
Correspondence is based on the idea that one can influence something based on its relationship or resemblance to another thing. Many popular beliefs regarding properties of plants, fruits and vegetables have evolved in the folk-medicine of different societies owing to sympathetic magic. This include beliefs that certain herbs with yellow sap can cure jaundice, that walnuts could strengthen the brain because of the nuts' resemblance to brain, that red beet-juice is good for the blood, that phallic-shaped roots will cure male impotence, etc.