What Is Poison Sumac?

Mary Elizabeth

Poison sumac (Toxicodendron vernix) grows as a large shrub or a small tree. It is the largest of three related plants in the cashew family all of which can cause skin irritation, the other two being poison ivy and poison oak. The poison sumac is distinguished by having the appearance of an ornamental, with large, alternate, toothless leaves, attractive clusters of fruit that is white when ripe, and brilliant fall foliage coloration.

Contact with poison sumac may result in severe itchiness.
Contact with poison sumac may result in severe itchiness.

Poison sumac grows mainly in the eastern United States. It is found in the South in eastern Texas, Louisiana, Mississippi, Alabama, Georgia, Florida, South Carolina, North Carolina, and Maryland, Delaware, and in small areas of Tennessee, Virginia, and West Virginia. In the North, it makes small appearances in Minnesota, Illinois, and Maine, and is found more prominently in Wisconsin, Michigan, Indiana, Ohio, Pennsylvania, New Jersey, New York, Connecticut, Rhode Island, Massachusetts, New Hampshire, and Vermont.

Poison sumac is more toxic than the poison ivy plant.
Poison sumac is more toxic than the poison ivy plant.

Urushiol is one of the chemicals that causes the toxicity associated with poison sumac. Over 90 percent of all people are allergic to it, but some are more sensitive than others. The oil is potent for up to five years after release, so even a dead plant can cause poisoning. Symptoms may not occur until seven to ten days after exposure for the first-time sufferer.

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Poison sumac grows mainly in the eastern U.S.
Poison sumac grows mainly in the eastern U.S.

Symptoms of contact can vary with the amount of exposure and the number of times one has previously been exposed. Possible symptoms include skin redness, itching and burning sensation, swelling, and blisters. If the toxin is swallowed or breathed, which can happen if the sumac is burned, the results may be life-threatening, and emergency treatment should be sought immediately.

A tube of steroid cream, which can help with itching from poison sumac.
A tube of steroid cream, which can help with itching from poison sumac.

Although the standard warning for poison ivy is about its leaves, poison sumac is more broadly toxic. Not only are the leaves toxic, but so are its flowers, fruit, twigs, bark, and sap. Sap stuck under the fingernails or sap residue on shoes, gardening tools, clothing, or pets can be transferred at a later date. As little as a nanogram of urushiol may be all that is needed to cause a rash.

Immediate washing with soap and water may prevent any reaction, but even an hour after contacting the toxin may be too late, although it will still prevent spreading. Any contaminated items that have come in contact with poison sumac, such as clothing, should be isolated and washed with hot, soapy water. Health care providers may recommend an antihistamine or steroid cream to help relieve itching.

Skin redness, itching and burning are typical symptoms of poison sumac contact.
Skin redness, itching and burning are typical symptoms of poison sumac contact.

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Discussion Comments


This is a really informative article. It exposes some of the myths out there about poison sumac and the others. When I was young, I always heard the phrase "leaves of three, let them be." That clearly is wrong since poison sumac doesn't have three leaves. I've also head that dead plants won't do anything, which is another myth.

The worst one out there is probably that if you don't get a skin reaction the first time you touch poison sumac, that means you have immunity. That is so wrong! I'm glad you've clarified here that that is not the case. Not only does it take about seven days for symptoms to show up, it also gets worse every time you are in contact with poison sumac. The more you are exposed to it, the more allergic you become.


I grew up in Ohio and everyone I knew had come into contact with poison ivy or poison oak at some point, because both are really common there. But poison sumac is not as well known and most people don't even know how to differentiate between them. I moved to Virginia about ten years ago and that's where I first ran into poison sumac. It really does look quite different than poison ivy and poison oak.

Both poison ivy and poison oak have three large leaves but poison sumac has many long oval leaves, at least seven of them on a branch. I don't know if this is true for all, but the poison sumac I saw had orangish, reddish leaves.


There is something called tecnu that we used a lot when we went hiking and camping. After we'd been around poison sumac, we would apply this on our skin and wash off with water. We didn't have access to showers obviously, so this was a good way to prevent irritation from developing.

Since poison sumac is so potent, if the area with the irritation isn't washed and treated, it can actually spread and even develop into an infection. One of my friends had this happen to him. It was just red at first and he ignored it for a couple of days and it started to spread and blister.

You can try and wear long clothing if you know you are going to be around poison sumac. But if it's too late to do anything about it, you can at least clean it with a cleanser and water to prevent it from spreading.

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