Lemons and limes were used to prevent scurvy.   A friend of mine, Frank,  believes fresh squeezed lemon or lime juice will protect you from "traveler's diarrhea".  He always requests the citrus with the meal and squirts the juice into water on directly into his mouth after the meal. (more)
Left: Lime flower, Dominican Republic.

Lime: To a home made chicken or vegetable soup add the juice of one lime (ie one lime to quart of soup). Also, try lime and ginger tea to soothe stomach and facilitate digestion.