Nizoral is used to treat and prevent dandruff and its symptoms such as dry, flaky, red, itchy scalp. This Anti-Dandruff, Anti-Psoriasis and Seborrheic Dermatitis Shampoo is dermatologically tested. It works by treating the underlying cause of dead skin, which is mainly a consequence of dandruff or psoriasis, by restoring your scalp back to its normal healthy state. Ketoconazole is the active ingredient proven to fight dandruff, psoriasis, itchy scalp and yeast infection.