Because someone asked:
Against dandruff, I would use a birch sap "hair water" - a specific brand I get from Germany (and is very expensive here in the United States) is "Seborin". Another brand might be by Weleda. - This is used after washing your hair, and is left in to dry.
You could also make yourself a hair oil with olive oil and some essential oil, like rosemary, oregano, tea tree or neem. Rub it in before washing your hair. Leave it on over night, then wash it out.
Also, dandruff might have to do with what you eat: Avoid dairy, sweets, alcohol and white starches (which are nothing more than sugars in a long chain). And alcohols are a form of sugar, too.
Food for healthy hair: nuts, beans, lentils, garbanzo, carrot, vegetable, brown rice, good proteins from poultry, lamb, and seafood; fish oil, zinc.