Answer. The acid commonly used to treat swelling due to a wasp sting is acetic acid, also known as vinegar. Vinegar is a weak acid that can help alleviate the symptoms of a wasp sting. It can be applied topically by soaking q cotton ball or cloth in vinegar and placing it on the affected area. The acidic nature of vinegar helps to neutralize the venom and reduce inflammation, providing relief from swelling and discomfort.
