From the manufacture's web site..
"Denorex controls dandruff, psoriasis and seborrheic dermatitis and is effective in relieving dryness, itching and flaking; while added conditioners leave hair healthy, shiny and manageable.
Denorex is used for treating and preventing itching, flaking and scaling of the scalp caused by dandruff and seborrhea. Denorex Shampoo is an anti-seborrheic that works by slowing the production of skin cells, which helps to reduce flakiness. "

THIS STUFF IS AMAZING!!!
It smells awful though! Menthol and tar...YUM!
BUT, it really REALLY works! I have seborrhea (oily, crusting or scaling skin). When I was 14yrs old I had a horrible time controlling the scaling on my scalp. My Mom tried so many remedies without any progress. I lost most of my hair because the scales were so thick that new hair could not grow or breathe. Then one day I tried this. It stunk so bad, but when you message it on the scalp it tingles. I would leave in on for about 5mins during treatments. It took about 2-3 months and my scalp was cleared. My hair grew back and so did my confidence.
I still get issues with my scalp but when I do I just do a treatment. About once a week or month, depending on the season.
I just cannot express how much I love this product!