# The Biological Science Behind Flatulence and Odor Understanding why intestinal gas is a natural byproduct of healthy microbial activity. - **Source:** [Dong-A Ilbo](https://www.donga.com) - **Published:** 2026-11-10 - **Topic:** [health](https://brifing.si/c/health) - **Original article:** - **On Brifing:** https://brifing.si/s/f383c73d-44da-4151-a707-9be47a4824aa ## Natural Physiological Process Flatulence serves as a primary indicator that gut bacteria are performing their essential roles within the digestive system. This process involves the breakdown of food particles that remain undigested after passing through the stomach and small intestine. It is a fundamental biological function rather than a sign of underlying illness. ## Microbial Chemical Factories Intestinal microbes function like miniature chemical factories during the digestive process. As they break down complex dietary fibers, they produce gases as metabolic byproducts. These gases mix with swallowed air and other substances generated during digestion, eventually traveling through the intestines to be expelled from the body as flatulence. ## Frequency and Health Benefits Healthy individuals typically pass gas between 14 and 20 times per day. This frequent expulsion is beneficial as it helps reduce internal abdominal pressure. By releasing these trapped gases, the body effectively prevents uncomfortable symptoms such as abdominal bloating, distension, and painful muscle cramps that can occur when gas accumulates. ## The Origin of Odor The distinct and often pungent smell associated with flatulence originates from the specific chemical compounds produced during microbial fermentation. While the majority of gas is odorless, trace amounts of sulfur-containing compounds created by bacteria contribute to the strong scent. The composition of these gases varies based on individual dietary intake. ## Role of Dietary Fiber Dietary fiber plays a critical role in gas production because it is not fully digested in the upper gastrointestinal tract. When this fiber reaches the large intestine, gut bacteria ferment it to extract remaining nutrients. This fermentation process is the primary driver for the volume of gas produced by the body. ## Swallowed Air Contribution Not all gas in the digestive tract is produced by microbial activity. A significant portion consists of atmospheric air swallowed during eating, drinking, or talking. This swallowed air, primarily nitrogen and oxygen, mixes with the gases generated by bacterial fermentation, altering the overall composition and pressure within the intestinal system. ## Microbiome Influence The human microbiome, a complex community of microorganisms residing in the gut, dictates the nature of digestive byproducts. Variations in the types and populations of these bacteria can influence how efficiently food is broken down. Consequently, the specific profile of an individual's microbiome directly impacts the frequency and intensity of flatulence. ## Clinical Perspective on Flatulence While often considered a social taboo, flatulence is a vital diagnostic marker for digestive health. Persistent changes in frequency or odor intensity may reflect shifts in dietary habits or the microbial balance. Understanding these mechanisms helps demystify a common physiological event that is essential for maintaining gastrointestinal comfort and health. ## Sources covering this story - https://www.donga.com/news/It/article/all/20261110/134997966/2 — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._