If you feel like you need a treat when you aren't feeling totally up to par, reaching for chocolate may not be a bad idea, as long as you choose the right type of chocolate. Chocolate has been used as a traditional remedy for diarrhea as far back as the 16th century in Latin American countries.
A study published in "The Journal of Nutrition" in October 2005 found that the flavonoids in chocolate may help keep your body from secreting excessive fluid, which is what happens when you have diarrhea. For the best results, you'll need to choose dark chocolate because it is the highest in flavonoids. The higher the cocoa content, the more flavonoids a chocolate contains. Milk chocolate could cause diarrhea in those who are lactose-intolerant, however, since it contains some lactose.