Nizoral anti-dandruff shampoo contains a medicine called ketoconazole. This belongs to a group of medicines called 'antifungals'. Like other shampoos, it also contains ingredients to clean your hair. Nizoral shampoo is used for fungal infections on the scalp and body such as: Dandruff Dry or greasy scaling of the scalp and other parts of the body called seborrhoeic dermatitis White to brown patches on the body that sometimes appear after being in the sun called tinea versicolor or pityriasis versicolor These conditions can be itchy. They are caused by a fungus (yeast) called Malassezia. This fungus is found on everyones skin, but sometimes it can overgrow and cause problems. Nizoral shampoo works by killing the fungus and stopping it from coming back. 2. What you need to know before