Aspirin contains acetylsalicylic acid, which is a form of salicylic acid and helps to relieve dandruff in an easy and fast manner. However, If you have thin, dry, and chemically damaged hair, salicylic acid in aspirin is not recommended for you. Aspirin can be used on oily hair because of its ability to deep-cleanse and prevent the excessive production of sebum. Even if you have oily hair, it should be applied to your scalp only once a week. As good as it can be for your hair, too frequent exfoliation may have a reverse effect and trigger excessive production of oil, as well as destroy the protective shield around the hair shafts.