Collodian wart paint containing: Salicylic Acid 16.7% w/w, Lactic Acid 16.7% w/w. The main active ingredient of this preparation is salicylic acid. Salicylic acid belongs to the group of medicines known as keratolytics. Salicylic acid works by breaking down keratin, a protein which forms part of the skin structure. This results in the shedding of skin cells from the affected area. In the treatment of warts, calluses and verrucae the effect of salicylic acid is to remove the affected skin over a period of time. If successful, the new skin which grows underneath will be healthy. The lactic acid is an ingredient which enhances the availability of the salicylic acid.