Poison Ivy, Oak, and Sumac Information Center

Fast Facts

*Urushiol Oil is Potent

  • Only 1 nanogram (billionth of a gram) needed to cause rash
  • Average is 100 nanograms for most people
  • 1/4 ounce of urushiol is all that is needed to cause a rash in every person on earth
  • 500 people could itch from the amount covering the head of a pin
  • Specimens of urushiol several centuries old have found to cause dermatitis in sensitive people.
  • 1 to 5 years is normal for urushiol oil to stay active on any surface including dead plants
  • Derived from urushi, Japanese name for lacquer
When the Japanese restored the gold leaf on the golden Temple in Kyoto, they painted the urushiol lacquer on it to preserve and maintain the gold. Guess you could say that you would be caught red handed if you stole it.

*Poison Ivy, Oak, and Sumac

  • Most common allergy in the country claiming half the population
  • Sensitivity to urushiol can develop at any time
  • Solutions or cures are those that annihilate urushiol
  • Everyone appears to react slightly different to all the remedies.
  • Covered by workers compensation in some states (CA, for example)
  • First published records of poison ivy in North America date back to 1600s
  • Poison Ivy coined by Captain John Smith in 1609
  • Western Poison Oak discovered by David Douglas (1799-1834) on Vancouver Island. Douglas fir also named after him.
  • People will serious deficiency in cellular (T-cell) immunity such as AIDS patients may not have problems with dermatitis.

*Myths vs. Facts

Myth Fact
Poison Ivy rash is contagious. Rubbing the rashes won't spread poison ivy to other parts of your body (or to another person). You spread the rash only if urushiol oil -- the sticky, resinlike substance that causes the rash -- has been left on your hands.
You can catch poison ivy simply by being near the plants Direct contact is needed to release urusiol oil. Stay away from forest fires, direct burning, or anything else that can cause the oil to become airborne such as a lawnmower, trimmer, etc.
Leaves of three, let them be Poison sumac has 7 to 13 leaves on a branch, although poison ivy and oak have 3 leaves per cluster.
Do not worry about dead plants Urushiol oil stays active on any surface, including dead plants, for up to 5 years.
Breaking the blisters releases urushiol oil that can spread Not true. But your wounds can become infected and you may make the scarring worse. In very extreme cases, excessive fluid may need to be withdrawn by a doctor.
I've been in poison ivy many times and never broken out. I'm immune. Not necessarily true. Upwards of 90% of people are allergic to urushiol oil, it's a matter of time and exposure. The more times you are exposed to urushiol, the more likely it is that you will break out with an allergic rash. For the first time sufferer, it generally takes longer for the rash to show up - generally in 7 to 10 days.

*How do you....

Want to know how to say poison ivy or oak in different languages? Look no further than the Poison oak and ivy translation project for your answer.