First, researchers grew enough fungus to give dandruff to 10 million people. Next, they sequenced its genes. Then they found out that not only does an icky fungus live on your head and cause dandruff --- but it could be having sex. On your head. Right now.
(Reuters, 7 Nov 2007)
This means no dandruff shampoo can really clear the balakubak (the local term for dandruff) problem.