Relieves Symptoms of Psoriasis and Seborrheic Dermatitis. For best results use at least twice a week or as directed by a physician. Keeps working even after you wash it off. Salicylic Acid is clinically proven to be effective in breaking down crusty, flaky build-up. Relieves itching and flaking from severe scalp conditions. Treats crust scalp build-up from Psorasis, dandruff and Sebhorreic Dermatitis.