Poison ivy is a plant that contains an oily resin called urushiol, which can cause a red, itchy rash when it comes into contact with the skin. Here are some tips for dealing with a poison ivy rash naturally and over the counter:

1. Wash the Affected Area: As soon as possible, wash the affected area with soap and water to remove any remaining urushiol oil on the skin. This can help prevent the rash from spreading.

2. Apply Cold Compresses: Applying cold compresses or ice packs to the affected area can help reduce itching and inflammation.

3. Use Calamine Lotion: Calamine lotion is an over-the-counter remedy that can help relieve itching and dry out blisters caused by poison ivy rash.

4. Take Oatmeal Baths: Taking oatmeal baths can help soothe itchy skin caused by poison ivy rash. Simply add a cup of oatmeal to a warm bath and soak for 20-30 minutes.

5. Apply Aloe Vera Gel: Aloe vera gel has anti-inflammatory properties that can help reduce itching and inflammation caused by poison ivy rash.

6. Take Oral Antihistamines: Over-the-counter antihistamines such as Benadryl can help relieve itching caused by poison ivy rash.

7. Avoid Scratching: Scratching can cause the rash to spread and increase the risk of infection. Try to avoid scratching as much as possible.

In severe cases, prescription medications such as corticosteroids may be necessary to treat poison ivy rash.