Resorcinol is a benzenediol. Resorcinol is commonly used in hair dyes and acne medication. Resorcinol works by breaking down rough, scaly, or hardened skin. Resorcinol also disinfects the skin to help fight infection. Resorcinol topical (for the skin) is used to treat pain and itching caused by minor cuts and scrapes, burns, insect bites, poison ivy, sunburn, or other skin irritations. Resorcinol topical is also used to treat acne, eczema, psoriasis, seborrhea, corns, calluses, warts, and other skin disorders. Resorcinol is included in the FDA final rule list of all permitted active ingredients for OTC topical acne products. Permitted combination active ingredient product - Resorcinol in 2 percent concentration in combination with sulfur in concentrations of between 3 and 8 percent. In oxidative hair dyes, resorcinol is regulated to 5% or below in practice, however, many manufacturers limit the level of free resorcinol in oxidative hair dyes to 1.25%. Resorcinol is limited to 0.5% in shampoos and hair lotions. Resorcinol is usually present in anti-acne preparations at a maximum concentration of 2%. The concentration of resorcinol can be much higher in peels, in some cases around 50%. Jessner’s solution (resorcinol in ethyl alcohol, 14% w/v; lactic acid, 14%; and salicylic acid, 14%) is commonly used in chemical peeling. A specialized medical use of resorcinol is in biological glues (gelatin–resorcinol–formaldehyde glue) for cardiovascular surgery, in particular aortic operations.