Poison ivy may look harmless, but woe to the person who comes into contact with it. Poison ivy will give you a rash on your skin that is caused by the toxin urushiol. Many people are allergic to this oil, but even if you’re not, the burning rash you get from it will make you want to scratch your skin off. Rather than waste money on store-bought cream or medication, you can use baking soda as a quick, simple and inexpensive cure.

Poison ivy, or poison oak, is a vine plant with three almond-shaped leaves and grayish-white berries common in North America. It is well-known for the toxin it produces, called urushiol, which causes an itching rash in most people. Urushiol is a clear oil that comes out of the leaves and stem and binds to the skin on contact, where it causes inflammation and then blistering. In severe cases, clear fluids are discharged from open blisters.

If you’ve been infected with poison ivy, run hot water over the affected area as soon as possible, preferably within the hour. Do not scrub or use a washcloth. This will make your skin feel extremely itchy, but the water will decrease your exposure to the toxin.

Don’t use the month-old box of baking soda that’s been sitting in your fridge and losing effectiveness. Instead, buy a box of fresh baking soda from any supermarket or drugstore. Run a warm bath and add a half to a full cup of baking soda to the water. Soak in the bath for up to a half hour. Small blisters on the irritated skin may form if they haven’t already.

After getting out of the bath, make a paste using three tablespoons of baking soda and one tablespoon of water and apply to the affected area. It will dry quickly and leave a white powder residue, so be careful not to accidentally rub it off. Baking soda seems to pull the urushiol from the skin; so by the time it dries, it should relieve the pain.

Wash everything. Urushiol oil, like most oil, adheres to surfaces; so anything that may have come into contact with the poison ivy, from your clothes to a purse or knapsack to the steering wheel of your car (or whatever else you may have touched), needs to be thoroughly scrubbed with soap and hot water or you will continue to reinfect yourself for weeks.

If a large portion of your body has been infected by poison ivy, or you get it in your eyes, nose or mouth, see a doctor immediately.