The human body produces a variety of odors in the form of volatile chemical substances that stimulate the sense of smell. While most of these body odors are considered socially unpleasant, there are a few that are considered benign and some that are believed to serve as attractants. Those odors considered to be most noxious are produced in the intestinal tract, the mouth, on the feet, and under the arms.

Intestinal tract gas, known medically as "flatus," is a normal product of digestion. Flatus is generated when bacteria that reside in the gut process the carbohydrates in food that cannot be broken down by digestive enzymes, or from swallowing gas-containing substances such as carbonated beverages or excessive amounts of air. The nature of its odor depends on the types of bacteria that colonize the human intestinal tract, as well as the types of food that are...