Prell is a brand of green shampoo that has been around since the 1950s. It was originally developed to help remove chlorine from hair after swimming, but it has since become a popular choice for those looking for a gentle and natural shampoo. Prell is known for its mild formula and its ability to cleanse without stripping away natural oils. It is also free of sulfates, parabens, and other harsh chemicals, making it a safe and effective choice for all hair types.