Nizoral Anti-Dandruff Shampoo (100ml). Nizoral Dandruff Shampoo is used to treat and prevent dandruff and dry or greasy scaling of the scalp (seborrhoeic dermatitis), which is a more severe kind of dandruff.. The shampoo contains ketoconazole, which is an antifungal that targets an increased number of yeasts on the skin called Malassezia.. These yeasts occur naturally on everyone’s skin, however, people with dandruff and seborrhoeic dermatitis seem to have more Malassezia.. The shampoo also treats the inflammation associated with dandruff, relieving scalp redness and itching.