Shampoo is a romantic comedy starring Warren Beatty as George, a hairdresser in Beverley Hills who spends his time, when he is not cutting hair, having sex with lots of women including the likes of Goldie Hawn and Carrie Fisher in her first film role.
The film is set in the late 1960s around the election of Nixon. In changing times George is unhappy with his life, although he is the star in the salon, he hates being there and wants to start out on his own. However unable to get working capital from the banks he turns to a rich woman (Julie Christie) instead...
It's a fun film with plenty of satire and style. George's life is totally chaotic but he comes across sympathetically despite his serial promiscuility. It is a comedy but not one you laugh at loud at (apart from a few notable times). Maybe it is more a tale of how you can't always get what you want... especially if you want it all.
The blaxploitation film Black Shampoo is based on this, though only very loosely...