A mustard bath is a natural remedy for a hangover, according to HowStuffWorks. Adding mustard to a bath increases circulation in the body and empties organs of impurities, allowing healthy, clean blood to enter the organs.
Using mustard in its typical store-bought form effectively treats hangovers, but HowStuffWorks suggests using a mustard bath powder instead. A recipe for homemade mustard bath powder consists of 2 tablespoons of mustard powder added to running warm bath water. The individual should soak in this mustard bath for 20 minutes before drying off and taking a nap to allow the mustard to treat the hangover.