Doctrine of signatures

{{significantly problematic}}{{altmed}}
{{cquote|Leading people to believe that they can treat depression by eating walnuts because they look like brains is dangerous and irresponsible, just like saying homeopathy can treat, oh I don’t know, ''anything at all''. These are dead theories, and their rotting corpses must be buried to keep them from stinking up the place.|||Matt Simon<ref>Simon, Matt. [https://www.wired.com/2014/07/fantastically-wrong-doctrine-of-signatures/ Fantastically Wrong: The Strange History of Using Organ-Shaped Plants to Treat Disease]. Wired.com, July 16, 2014.</ref>}}
The '''doctrine of signatures''' was a concept developed in ancient Europe that claimed that [[plants]] advertised their usefulness to [[humans]] and [[animals]] by looking like the things they aided. In addition to the plants looking like human body parts, animals or other objects, the doctrine of signatures could also refer to the environments or specific sites in which plants grew.

==Christianity==
Late [[medieval]] [[Christian]] [[theologian]]s embraced the concept as a natural extension of the idea that the [[Creator]] carefully ordered his [[creation]] such that careful observation would reveal useful information about the plant. Walnuts that looked like the cranium would be used for headaches, or beans that looked like livers would cure liver problems. Beyond medical applications theologians extended this concept to plants representing all the right doctrines of Christianity. This is most aptly seen in the Passionflower (''Passiflora incarnata'') whose symmetry and numerical elements were said to be representative of [[Jesus Christ]]'s passion.

[[File:Hortus sanitatis 1491 Mandrake.jpg|thumb|right|165px|A mandrake, from: Jacob Meydenbach: ''Hortus sanitatis'', 1491]]
Mandrake (''Mandragora'' spp.), whose roots sometimes contain bifurcations causing them to resemble human figures showing off their legs, in [[Hebrew]] is "love plant". There are classical [[Jewish]] commentaries which suggest that mandrakes help barren women to conceive a child.<ref>see {{bible|Genesis|30|14}}: And Reuben went in the days of wheat harvest, and found mandrakes in the field, and brought them unto his mother Leah. Then Rachel said to Leah, Give me, I pray thee, of thy son's mandrakes.</ref>

==Homeopathy==
[[Homeopathy]] has often called upon the doctrine of signatures for finding potential [[herb]]s to use in their cures. Despite its complete rejection as a valid theory for classification of plants or their properties and uses in medicine, many homeopathic and [https://web.archive.org/web/20081005063837/http://www.manataka.org/page1429.html other] "natural" practitioners still use the concept today.

==Examples==
Some examples of plants and their "uses" based on the doctrine of signatures:
*Lousewort (''Pedicularis'' spp.) &mdash; thought to be useful in repelling lice
*Spleenwort (''Asplenium'' spp.) &mdash; thought to be useful in treating the spleen
*Liverwort &mdash; thought to be useful in treating the liver
*Toothwort (formerly ''Dentaria'' spp., now ''Cardamine'' spp.) &mdash; thought to be useful in treating tooth ailments
*Hedge woundwort (''Stachys sylvatica'') &mdash; has antiseptic qualities
*Lungwort (''Pulmonaria'' spp.) &mdash; used to treat pulmonary infections
*Wolfsbane (''Arnica montana'' or ''Aconitum'' spp.) &mdash; used to treat [[Lycanthropy]]

==See also==
*[[Sympathetic magic]] &mdash; the more general concept of "like affects like"

==References==
{{reflist}}

[[Category:Alternative medicine]]
[[Category:Arguments against evidence-based medicine]]
[[Category:Plants]]

Categories: Alternative medicine, Arguments against evidence-based medicine, Plants