Doctrine of Signatures

In ancient times, long before reference books could be consulted, a method of herbal identification came about based on the belief that various physical features of a plant were directly linked to the plant’s therapeutic effect in the human body.

It is referred to as the Doctrine of Signatures, and in a time when knowledge of medicinal plants was passed on by word of mouth, it proved a practical way of remembering a plant’s properties.

This practice was in part a spiritual one as it was believed that God marked his creations with a clear indication or ‘signature’ of its purpose. Groups of plants sharing the same signature were thought to have similar healing properties or have a healing effect on similar parts of the body.

Paracelsus (1493-1541), considered the father of modern chemistry, did much to popularise the Doctrine of Signatures and its applications. He believed that plants grow where they are most needed, for example dock leaves were used to treat the sting from a nettle plant, and these two plants were often found growing close together.

Aspects of the plant which were thought to give indications to its use include:

Habitat of the plant

Colour – of flower, fruit, root or stem

Shape

Texture

Odour

Some of the most reputed examples of the doctrine of signatures from that time include lungwort whose spotted leaves were believed to resemble a diseased lung, walnuts which were considered to be shaped like the human brain, and ginseng root which was used to assist male sexual vitality due to its resemblance to male reproductive anatomy.

Modern herbalism has confirmed some of these earlier observations, for example lungwort is an expectorant herb used to help clear mucus from the lungs and walnuts with their omega 3 content are considered beneficial for brain health.

Some examples of the doctrine of signatures:

HABITAT	HEALING PROPERTY INDICATED	PLANT
Wet lowlands, swamps	Associated with diseases of wetness; rheumatic disorders, feverish colds and coughs	Mints, Verbena, Elder
Banks of clear ponds and rivers	Associated with diuretics - helping to cleanse the urinary system	Horsetail, Mints

 

COLOUR	HEALING PROPERTY INDICATED	PLANT
Yellow flowers/fruits	Disorders of the liver, gall bladder, spleen	Dandelion, Tansy, Lemon
Reddish flowers/fruits	Blood purifier, alterative, cardiovascular system	Red clover, Hawthorn

 

SHAPE	HEALING PROPERTY INDICATED	PLANT
Tube-like bronchial apparatus	Coughs, throat infections	Green tops of Garlic and Onion
Flowers resembling eyes	Diseases of the eyes	Eyebright, Chamomile

 

TEXTURE	HEALING PROPERTY INDICATED	PLANT
Sharp thorns, prickles	Acute sharp pain - some of these herbs are not pain relievers but are efficient in acting at the causes of the pain.	Strammonium, Thistle
Exudations - resinous and balsamic	Heals most cuts, lesions and ulcers of the skin	Aloe vera

 

ODOUR	HEALING PROPERTY INDICATED	PLANT
Strong smelling	Drive away evil spirits	Rue, Frankincense
Pleasant smelling	Deodorisers for body odour	Rosemary, Sage Thyme

 

Today we are fortunate enough to have a multitude of reference books to guide us on the traditional applications for many plants as well as emerging scientific evidence to clarify the actions and therapeutic benefits of herbs.

Whilst it would no longer be regarded as practical or safe to prescribe herbs based on their physical features alone, they may give us clues to identifying their full spectrum of uses. 

Written by Aimee Wilkins   BHSc. (Nat.), N.D., Dip. Nut.