Unit 4: Plants as Medicines

Several plants are widely used by different Indigenous North American cultures within the areas of their growth. In the prairies and east, yarrow (Achillea millaefolium) is used across Canada, and several species are also used for medicines in Europe. Photograph by Margaret Anderson.

Herbal medicine is often the aspect of plant knowledge people think of when they hear the word “ethnobotany.” Plants are used as medicines in all human cultures. In addition to nutrients and fibre, plants contain many other substances that may have biological activity. These compounds may be called “secondary compounds” because plants manufacture them for purposes of defence, rather than as an essential part of cellular metabolism or mechanical support. Plants, being stationary, cannot escape predation by herbivores except by evolving such physical defences as thorns, or by reducing palatability or digestibility—often through production of bioactive compounds that may have toxic properties. People in all environments have investigated the properties of plant preparations and used them in many different ways as part of their healing practices, as flavourings, and as poisons.

Objectives

By the end of this unit you should be able to

1. discuss the roles of plant phytochemicals and the healing context in the use of plant medicines.
2. provide examples of important healing plants used by Canadian First Nations and Alaska Natives.
3. describe the impact of world market forces on the use and availability of medicinal plants to traditional peoples and to First World consumers.
4. examine the implications of intellectual property rights issues in relation to traditional knowledge with reference to healing properties of plants.