In the broadest sense, “no poo” means no shampoo. It’s a philosophy and method of cleaning your hair without traditional shampoo. People are attracted to the no-poo method for a number of reasons.

Poo anxiety, bashful bowels, shy bowel syndrome: they're all terms for what's medically known as parcopresis or difficulty pooping when you're not at home. The Germans have given a name to this ...