Most shampoos contain some form of alkali, usually in the form of sodium lauryl sulfate or sodium laureth sulfate. These ingredients help to remove dirt and oil from the hair and scalp, and they can also help to create lather. However, some people may find that shampoos with alkali can be harsh and drying to their hair, especially if they have dry or damaged hair. If you have sensitive skin or dry hair, you may want to consider using a shampoo that is free of alkali.