Clearasil Ultra Gel 4-Hour Treatment is formulated with Acceladerm technology that starts working instantly to deliver maximum strength acne medication deep into the pores. Dermatologically tested, it contains 2% salicylic acid to help clear up your skin. Within four hours of application, this 1.0-oz Clearasil Ultra Acne Treatment Gel will begin to visibly reduce redness associated with acne and decrease pimple size. Highly effective, it can also be used as a spot treatment during an acne breakout.