Selerex Dandruff Shampoo is a pure medical grade anti-dandruff treatment containing Selenium Sulfide as its active ingredient. This specialized formula targets the root cause of dandruff to provide effective control and relief from flaking and scalp irritation. The shampoo contains Selenium Sulfide which is a proven anti-dandruff ingredient that works by targeting and eliminating the underlying causes of dandruff. As this is a medical grade product, it should be used as directed for best results in controlling dandruff symptoms. The 200ml size provides sufficient product for an extended treatment period.