Acnecide Face Gel 5% contains the active ingredient Benzoyl Peroxide, which kills the bacteria (germs) known as Propionibacterium acnes, one of the main causes of acne. Acnecide Face Gel is for the treatment of mild acne on the face, in adults and adolescents 12 years and over. Mild acne appears as predominately blackheads and whiteheads and there are few or no spots and pimples and no inflamed spots.