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POISONOUS PLANTS

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	poison ivy  	poison oak
Photos courtesy of Edwin P. Ewing, Jr., (poison ivy) and U.S. Department of Agriculture (poison oak)

Overview

Many native and exotic plants are poisonous to humans when ingested or if there is skin contact with plant chemicals. However, the most common problems with poisonous plants arise from contact with the sap oil of several ever-present native plants that cause an allergic skin reaction—poison ivy, poison oak, and poison sumac.

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Protecting Yourself from Poisonous Plants:  Print or order this free card for easy access to important safety information.

Poison ivy, poison oak, and poison sumac release an oil, urushiol, when the leaf or other plant parts are bruised, damaged, or burned. When the oil gets on the skin an allergic reaction, referred to as contact dermatitis, occurs in most exposed people as an itchy red rash with bumps or blisters. When exposed to 50 micrograms of urushiol, an amount that is less than one grain of table salt, 80 to 90 percent of adults will develop a rash. The rash, depending upon where it occurs and how broadly it is spread, may significantly impede or prevent a person from working. Although over-the-counter topical medications may relieve symptoms for most people, immediate medical attention may be required for severe reactions, particularly when exposed to the smoke from burning these poisonous plants. Burning these poisonous plants can be very dangerous because the allergens can be inhaled, causing lung irritation.

Outdoor workers may be exposed to poisonous plants. Outdoor workers at risk include farmers, foresters, landscapers, groundskeepers, gardeners, painters, roofers, pavers, construction workers, laborers, mechanics, and any other workers who spend time outside. Forestry workers and firefighters who battle forest fires are at additional risk because they could potentially develop rashes and lung irritation from contact with damaged or burning poisonous plants. It is important for employers to train their workers about their risk of exposure to poisonous plants, how they can prevent exposures and protect themselves, and what they should do if they come in contact with these plants.

How Poison Ivy Works

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