There is evidence of herbs as medicine in virtually every civilization that has appeared on earth -  including ancient Egypt, China, India, Arabia, Europe, historical Britain, the indigenous peoples of Australia and ancient Rome.  

Centuries ago, the ‘Doctrine of Signatures’ was a popular concept.  This was the belief that God had ‘stamped’ on plants the keys to deciphering which herbs were to be used for different  ailments.  By looking at the size, shape, and color of the plant, and seeing if it matched a body  part or characteristic would influence which herbs chosen for healing purposes.  For instance, a yellow-colored plant may have been used for disorders associated with the liver, and heart-shaped leaves were used for heart problems.

Different parts of herbs are used medicinally.  For some herbs the flowers are the part commonly used, in others the berries, seeds, leaves, roots/bulb, sap, or bark are considered medicinal.  The part used may have an effect on the herb’s therapeutic action – for instance, American Indians used to use the root of the Echinacea plant.  Modern research has shown that it is the root of a certain  species of Echinacea that has a higher level of the active constituent than the leafy parts of the plant.