Colon Gas and Flatus

Medical Conditions

Author, Frank W. Jackson MD
Updated 2014


The colon is home to a myriad number of different bacteria. This dense, thriving mixture of over 1,000 different species is a true living health laboratory, producing many health benefits if it is treated and fed properly. Many of these bacteria within the colon are gas formers. This is normal and 99% of these colon gases are harmless and odorless.

What Are These Gases?

  • Hydrogen – This is a major part of colon gas. It is made by bacteria and, indeed, is used by other bacteria in their own metabolism.
  • Oxygen – This is the same gas as is in the air we breathe.
  • Carbon dioxide – Most cells in living organisms make this gas, so it is not surprising that bacteria do so as well.
  • Methane – About 40% of people make this odorless but explosive gas. It was always thought to be inactive but now some current research indicates that it might contribute to constipation.
  • Trace gases – These are present in very tiny amounts, but since most are based on sulfur (like garlic), certain bacteria will create smelly sulfide gases, even when present in very small amounts.

What Is a Normal Amount of Colon Gas and Flatus?

The amount produced each day varies widely. Every person will have her or his own characteristic makeup of bacteria, which stays pretty much the same over long periods of time. So, the amount of colon gas will depend on the genetic makeup of the person. Furthermore, the amount of gas created will also depend on the types of foods eaten. So, the total daily amount can vary between a pint of gas to several quarts each day. The normal number of passages of gas or flatus ranges between 10 and 20 per day.

  • Colon gas depends on a person’s genes and the foods eaten.
  • 10-20 passages of gas per day is normal.


This sugar is used as a non-caloric sweetener in some chewing gums and many diet foods. It acts exactly like lactose in the colon, producing excess colon gas and, in some, diarrhea.


  • beans and legumes – Most vegetables in this category contain certain types of carbohydrates that are not digested in the small bowel but, again, are fermented in the colon.
  • cruciferous vegetables – Brussels sprouts, cabbage, cauliflower, and broccoli are noted by some to cause excess gas. This is an interesting group as these vegetables also contain large amounts of an anti-cancerous substance called sulforaphane. You should eat as much of these vegetables as you can tolerate.
  • carbonated beverages – These contain carbon dioxide, most of which is belched back up or absorbed. Very little reaches the colon.
  • fiber – Fiber is a critically important part of the diet. Almost all plant food contains both insoluble (no gas) and soluble fiber (may form gas). We all know that increased fiber is a very important part of the diet. If we get too much of the soluble type, then the colon bacteria can manufacture excessive gas. A newly discovered form of fiber is prebiotics. These soluble plant fibers have been found to allow many health benefits to occur in the colon.

What To Do?

There is no one answer that is right for everyone. However, as a first step, you need to decide what is most important to you. As a physician, I would always recommend that vegetables, fruits, seeds, and nuts, are at the top of the list, as the fibers, antioxidants, and cancer preventing parts of these foods cannot be obtained elsewhere. For detailed recommendations, go to Colon Gas & Flatus Prevention Diet. In short, I would recommend:

  • increase fiber in the diet gradually.
  • beans and legumes are a wonderful source of protein and fiber, though if it contributes to colon gas, they should be used only
  • use milk and dairy products carefully if you are intolerant of lactose.
  • give up sorbitol in chewing gum and diet foods. From a health standpoint, it only sweetens. It does nothing more.
  • fiber supplements, especially prebiotic fiber supplements, should be added in only small amounts for the first week of use. Take perhaps half the recommended dose. Then gradually increase them to

So That’s It

You can’t change your genes. You can change what you eat and drink. By doing so in a careful, reasonably planned manner, colon gas can be controlled in just about everyone.