Poison Ivy, Oak, and Sumac

Identify poisonous plants and respond to exposure

Why These Plants Cause a Rash

Poison ivy is a harmful vine or shrub in the cashew family. It grows widely in parts of the United States and southern Canada, often climbing tree trunks or spreading across the ground. When it has no support to climb, it may form an upright bush.

Poison ivy, poison oak, and poison sumac contain urushiol, an oily plant compound that can cause an itchy, blistering skin rash after contact. The oil can transfer to skin, clothing, shoes, tools, pets, and other gear.

Even dead plants in underbrush can retain urushiol and transfer it to your skin. A rash itself is not contagious, but contact with oil remaining on skin, clothing, or equipment can spread exposure.

Illustration of poison ivy with three leaflets
Poison ivy commonly has clusters of three leaflets.

Identifying the Plants

Illustration of poison oak leaves
Poison oak leaves can resemble oak leaves.

Poison ivy leaves are often red in early spring, shiny green through the growing season, and yellow, red, or orange in autumn. Each leaf usually has three leaflets: two form a pair on opposite sides of the leafstalk, while the third stands alone at the tip.

Small greenish flowers may grow in clusters near where the leaves join the stem. Later in the season, whitish, waxy, berry-like drupes can form. Plant appearance varies by region and season, so do not rely on color alone.

  • Poison ivy Usually a climbing or ground-covering vine, but it can grow as an upright shrub. Commonly has three leaflets.
  • Poison oak Typically grows as a shrub. Its leaves can resemble oak leaves and may also occur in groups of three.
  • Poison sumac Typically grows as a shrub or small tree in wet areas of the eastern United States. It has compound leaves with multiple leaflets.

If You Touch One

Wash exposed skin as soon as possible. Prompt washing can reduce the amount of urushiol absorbed by the skin and may lessen the reaction.

  • Rinse the exposed area with plenty of lukewarm water. If available, use rubbing alcohol, a poison-plant wash, or dish soap, then rinse thoroughly.
  • Wash gently with soap and water; avoid harsh scrubbing, which can irritate the skin.
  • Clean under your fingernails, where urushiol can collect and spread.
  • Remove contaminated clothing and wash it separately with detergent and hot water.
  • While wearing gloves, clean shoes, tools, backpacks, bike parts, and other gear that may have contacted the plant.
  • Wash pets that may have contacted the plant, using appropriate pet-safe products.
Do not burn poison ivy, oak, or sumac. Burning these plants can release urushiol into the air, where inhaling it can cause serious respiratory irritation.

Treating the Rash

  • Try not to scratch; scratching can irritate the skin and increase the risk of infection.
  • Apply cool, wet compresses to itchy areas.
  • Use calamine lotion or hydrocortisone cream as directed to help reduce itching and blistering.
  • A lukewarm colloidal oatmeal bath may soothe itchy skin. Avoid very hot water, which can worsen itching.
  • An oral antihistamine may help relieve itching for some people; follow the package directions.
  • Leave blisters alone. Do not remove loose skin from open blisters.
Get medical help if the rash is severe, covers a large area, affects the face or genitals, shows signs of infection such as pus or yellow crusting, or does not improve. Seek emergency care for swelling or difficulty breathing.

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