Definition of Poison ivy - oak - sumac:

Poison ivy, oak, or sumac poisoning is an allergic reaction that results from touching the sap of these plants. The sap may be on the plant, in the ashes of burned plants, on an animal, or on other objects that came in contact with the plant, such as clothing, garden tools, and sports equipment.

Small amounts of sap can remain under a person's fingernails for several days unless it is deliberately removed with very good cleaning.

Poisonous Ingredient:

One poisonous ingredient is the chemical urushiol.

Where Found:

• Bruised roots, stems, flowers, leaves, fruit
• Pollen of poison ivy, poison oak, and poison sumac