Question: how often to wash your hair if you have dandruff?
Answer: Dr. Kaplan recommends a medicated dandruff shampoo (which you can find at drugstores) every day, one that contains ketoconazole, selenium sulfide, or zinc. If your hair is coarse, though, and you're concerned that daily shampooing will make it more brittle, you may want to use a dandruff conditioner too.