Poison oak can be a harmful plant if you touch it, as its urushiol oil will cause a nasty rash.
What's the Difference Between Poison Oak and Poison Ivy?
“Leaves of three, let it be!” “Hairy vine, no friend of mine!” Learn how to spot poison oak, tell the difference between poison oak and poison ivy, and treat a poison oak rash.
What is the Difference Between Poison Oak and Poison Ivy?
Poison oak is a relative of poison ivy. There are many similarities:
- Both plants contain the same toxic resin, urushiol, in all parts of the plant (toxic to humans but harmless to animals).
- Both plants have three leaflets, white flowers in spring, and can grow as a vine or a shrub.
- Leaflets can range in size from the length of your thumb to the length of your hand.
- A middle leaflet has a notably longer stem than the two side leaflets, though more obvious in poison ivy than in poison oak.
- Depending on the season, leaf color can range from green to orange and even a dark purplish-red.
But they are indeed different plants. In North America, there are two species of poison oak: Atlantic (Eastern) and Pacific (Western).
Read Next
How to Identify Poison Oak
- Poison oak is a low-growing, upright shrub that can reach about 3 feet tall, sometimes resembling a vine.
- The leaf shape resembles an oak leaf (hence the name, poison oak), but it’s not a member of the oak family.
- Leaflets are duller green than poison ivy and usually more distinctly lobed or toothed.
- Leaflets have hairs on both sides, unlike poison ivy.
- Poison oak tends to grow at elevations between sea level and 5,000 feet.
- While the fruit of poison ivy is the color of pearls, poison oak fruit (called “drupes”) is tan.
At the end of the day, remember: Leaves of three, let it be. In other words, if you see a plant with clusters of three leaves, don’t touch it!
Poison Oak Symptoms
Symptoms of poison oak include itchy red rashes that resemble burns, swelling, and even blistering.
Symptoms can take 24-48 hours or even up to a week to show up, mainly if it’s your first exposure!
Poison oak, like poison ivy, contains urushiol. This oily substance causes a poison oak rash, which can be almost impossible to avoid. Upon contact with your body, urushiol immediately forms a chemical bond with the skin and causes an almost unstoppable allergic reaction. Urushiol will stay on clothes, pets, or other materials for months, and its potency lasts. You could even get poison oak without going anywhere near it.
The urushiol resin can cause harsher reactions for those who have been exposed to it before. Sensitivity to urushiol might decrease if you do not come into contact with it until later in life. Only about 15 percent of people are resistant to urushiol, so don’t feel safe around poison oak unless you are absolutely sure you are resistant. You also may become sensitive with repeated exposure, so your resistance might be short-lived.
Danger: Smoke inhalation from burning poison oak can send you straight to the emergency room. Avoid burning this plant (and poison ivy)!
Poison Oak Treatment
Treating poison oak within 10 minutes of contact is your best chance of avoiding a reaction.
Urushiol is not water-soluble! Use strong soaps (like dish soap) and wash with cold water to keep the oils from spreading. Cleanse the area of contact within the first ten minutes, then rinse off with cold water. As urushiol can remain active for years, you’ll want to wash any clothes, items, or furniture that may have come into contact with the invisible oily residue.
If you don’t catch the exposure immediately, treat the resulting itchy rash and blisters topically with calamine lotion, baking soda pastes, aloe vera, and many commercial products. If you don’t mind mixing breakfast and skin care, one tried-and-true remedy for itchy skin is oatmeal. Fortunately, poison oak is not contagious from the leaking serum, just the fresh urushiol.
If poison oak is extremely serious or you develop a severe reaction characterized by fever or feel generally ill, consult your doctor about a prescription. You should also see your doctor if the rash involves the eyes, mouth, or genital areas.
Of course, the best remedy is always prevention; study our photos so you can recognize poison oak.
Have you ever had a run-in with poison oak? Tell us about it in the comments below!
Samantha Caveny
ADVERTISEMENT
Various mixtures of water and vinegar, with possible addition of salt or dish liquid can be used to kill poison ivy. You will probably need to reapply every few days until you notice the plants drying up. Check the internet for different mixtures that work. Be aware that vinegar over sprayed on other plants may damage plants you are not trying to harm!
Hi, Barbara. There are many things that you can try. But firstly, remember to protect your body and eyes from the poison ivy/oak while attempting to remove it. Wearing proper protection, you can dig up the plants. You will have to get the entire root system and then dispose of it. Others swear by pouring boiling water at the base of the plants. This takes several applications, but when the plants began to wilt and shrink back, you can stop. You can try filling a sprayer with undiluted white vinegar and spraying the leaves and crowns of the plants. After either of these techniques, it would be best to dig out the plants. And here is a little less conventional method—try goats! Depending on where you live, farms will often rent out goats to eradicate unwanted plants. The poison ivy does not bother the goats.
I have found that treating the rash with Witch Hazel is very effective.
Witch hazel is a fantastic remedy for so many things!
OMgosh I’m so allergic to urishol it’s NOT funny. My head yes head swells the size of a basketball my eyes sweep shut so much so I woke up and thought I had gone blind! My legs had pustules blisters and scarlet coloring all the while weeping pus down my legs as I was demented in itching and crying in pain! And that was the first time I’m came in contact wit it, I was 9 years old. Now it’s worse!!!
At first sign go directly to a hospital emergency room.
Sheila-
That is horrible, we are so sorry to hear this! Poison Ivy can be so terrible.
When I was a youngster, I use to get poison ivy and oak every yr. Very miserable stuff. One year though I remember specifically, because I had got in poison oak and my left arm was so swollen and blistered up, the Dr.s thought they might have to ampitate it, if it didn't start getting better. I have always had to go get shots after getting poison ivy and oak, but that year didn't seem like shots were helping. When I got a little older, around 18, I used to work out of town for a hazardous material clean up crew. I ended up getting poison ivy on the job, out of state. My bosses brother took me to the hospital for a shot, the Dr. said he would fix me up. That was 30 years ago and I haven't had it since, until two days ago. Not sure what he gave me back then but it sure was worth the jab.
Good article thanks. But... You state poison oak growing to a height of only a few feet. Sorry to disappoint but i can show you poison oak vines 3”-4” in diameter at their base and growing to heights of 25’+ in amongst oak forests. If you go to Montaña de Oro State park on the Central Coast of California (near Los Osos and Morro Bay) and hike the Oats Peak trail or Manzanita trail or numerous others. Both the abundance, size and height of the poison oak will blow your mind. Also, hands down, the very best soap to use is is good old Pyrex Fels Naptha laundry soap bar. It’s pretty much straight Lye soap. Be sure to WASH TWICE in COLD WATER with plenty of Fels, rinse well both times with cold water. I’ve been climbing, hiking and mt. biking on the Central Coast for decades. I’ve spent weeks doing poison oak removal on a coastal ranch. Dug ditches through it installing plumbing systems. Clawed my way through it searching for new and old climbing routes. Been thrown ass over tea kettle off my mt. bike into thick growths of the stuff. I’ve been knowingly covered in poison oak more times than I can count. I’ve had it and it’s a painful experience I don’t ever want again. Fels Naptha works every time, even after hours of exposure. I take this subject seriously because I have a dear friend who back in the early 1990’s unknowingly made dream catchers along with her mom and sister, out of dormant/barren poison oak stalks. All three broke out bad within 24 hrs and were hospitalized and treated with cortisone injections. Her and her sister suffered hard in hospital for over four days and at home after for another week. But their mom got worse after day three, high fever to coma to death in five days from cerebral meningitis due to the urushiol poisoning. I have numerous other stories of run-ins with poison oak but that’s the worst of them.
I have lived in Santa Cruz, California for 35 years and can attest that indeed poison oak grows in huge shrubbery clumps/stands up to 12 feet high and unlimited widths as a stand from the coasts all the way up to the mountains. I regularly see vines up to 3"-4" circumference completely covering multiple trees in mixed forests. In fact, trees can look like poison oak trees once the vines get hold and take over. Even in the winter it can zap you as naked stems or vines. I carry a huge bottle of Tecnu in my car and always take it with me camping. Btw - your pet can be an endless source of exposure if they get the oil on their coat. I'm excited to hear about the Fels Naptha soap, but I hope I don't have to try it!!!! As a Wilderness Guide i'm always looking for the best interventions and treatments in the field, thanks.
