£6.49 – Acnecide contains the active ingredient benzoyl peroxide 5% which attacks the bacteria (germs) known as Propionibacterium acnes, one of the main causes of acne. Your Doctor or Pharmacist has recommended this medicine to treat your acne. Acne appears as blackheads and whiteheads which people often refer to as pimples or spots. You can use Acnecide on the face, neck and back.