Poisonous and Allergenic Plants
Nettle Rash

poison.jpgThroughout history, poisonous and allergenic plants have caused much discomfort to humans and animals alike. Varying in their effects, certain plants have more harmful consequences than others. Plants contain toxins that are so deadly that casualties can result from miniscule amounts. For example every par
t of the water hemlock is lethal, even a small mouthful can cause death. Glycosides and alkaloids are usually the toxic compounds in most plants. However some of these poisonous compounds can be used for medicinal purposes and as natural insecticides. Some plants can also cause allergic reactions that can be debilitating or even fatal. Allergies are hypersensitivity diseases caused by the immune system's response to harmless substances such as ragweed pollen or spores. Other allergic reactions, specifically to poison ivy, result in contact dermatitis. In addition plants can also cause mechanical injury by puncturing the skin via spines, thorns, prickles, burrs or hairs. The stinging nettle has protruding hairs that can puncture the skin and cause a rash.

Ancient uses

Curare Arrow Heads

In history poisonous plants have been used in a variety of ways. From the earliest times poisonous plants such as curare were used as arrow poisons to capture prey. Other poisonous plants were also used as a means of disposing of one's enemies. In ancient Athens, poisonous plants were used as a standard method of capital punishment. Knowledge about the use of toxic plants was prevalent in the Renaissance in Europe. For example, poisonous succession powders frequently ensured a timely death and a calculated ascent to power. Members of the De Medici family of Italy, specifically Catherine De Medici, were known to poison others. Over time, the knowledge about poisonous plants increased and their uses began to decline.

Levetin, Estelle, and Karen McMahon. Plants and Society. New York: McGraw-Hill Companies, 2007. Print.

Poison Ivy - Ragweed - Stinging Nettle - Curare - Water Hemlock