Acne vulgaris is by far the most prevalent of adolescent skin disease, involving 60-80% of the teenage population. By androgen-stimulation the production of sebum is increased and by hyperkeratinisation the canal of the pilosebaceous follicle will be closed, thereby causing formation of comedones. These will get infected with Propionibacterium acnes. The treatment of acne vulgaris therefore consists in 4 steps: sebosuppression (with Benzoylperoxid), keratolysis (with Vitamin A-acid and Azelainacid), bakteriostasis and stopping inflammation (with antibiotics). A mild cure of the affected skin is necessary too.