The CANADIAN POISONOUS PLANTS INFORMATION SYSTEM presents data on plants that cause poisoning in livestock, pets, and humans. The plants include native, introduced, and cultivated outdoor plants as well as indoor plants that are found in Canada. Some food and herbal plants are also included that may cause potential poisoning problems.

Plant poisoning is caused by chemicals in plants that have undesirable affects upon animals and humans. Some poisons must be ingested whereas others, such as chemicals in poison-ivy, only require contact to elicit response in sensitive humans. Some chemicals must be modified before they are poisonous to animals, such as prunasin and other cyanogenic glycosides. These chemicals must be hydrolyzed by plant enzymes or by rumen organisms.

Plants that cause dermatitis are discussed in this program if the reactions are severe. The more obscure dermatologic plants are not included. For more information on plant-induced dermatitis [see Mitchell, J. C., Rook, A. 1979. Botanical dermatology. Greenglass Ltd, Vancouver, B.C., Canada. 787 pp.].

Other excluded plants are those that only cause mechanical injury, poisonous blue-green algae, and plants causing hay fever.

While the Information System is oriented primarily to a Canadian audience, much of the information is useful elsewhere. Certainly the plants grown in and around homes can be grown throughout the temperate regions of the world. Indeed, many house plants are tropical in origin. Other plant species included here have been introduced to North America as well as other temperate regions of the world. The information on the native plant species is applicable wherever they grow in North America.

Information included in this program has the following limitations:

  • much literature on poisonous plants is anecdotal and therefore of limited reliability
  • many plants are only mildly poisonous or cause symptoms in unusual circumstances such as when prodigious quantities of material have been consumed
  • the author has attempted to find the most current literature available on each included plant species (up to the 1993 publishing date of the original document). However, in many cases, current information refers to works published early in that century.