Dandruff shampoo works to curb a flaky and itchy scalp. What they target depends on the ingredients. Dandruff shampoos usually contain antifungals or corticosteroids. Antifungals keep fungus from growing, which, in turn, reduces the fungi that cause dandruff. Some common antifungals in dandruff shampoo are ketoconazole, bifonazole, selenium sulfide, ciclopirox olamine, and zinc pyrithione. Corticosteroids are anti-inflammatory, which helps reduce irritation and thus flaking. Fluocinolone is a common corticosteroid in dandruff shampoos. Coal tar is yet another common ingredient that acts as an antifungal and anti-inflammatory.