Many people will pay close attention to the baby''s stool and obtain important information about the baby''s digestion and health status, but there may be few adults who pay attention to their stool and find important health (or disease) clues. Not to mention the subtle changes in feces. In clinical practice, many people have not noticed the obvious changes in feces, so that the diagnosis and treatment of serious diseases are delayed. Therefore, if you are responsible for your own health, you must abandon the traditional concept of "dung is dirty, pay attention to feces makes people sick", and at the same time take seriously this messenger from the intestine-stool. Even in academia, the study of human intestinal flora is relatively backward, probably because people do not like to deal with other people''s feces.

The main components of 　　 feces include ① water; ② dietary fiber; ③ bacteria; ④ unabsorbed nutrients; ⑤ other residues such as debris. Normal people defecate about once a day, and the total amount is about 100 to 300 grams. However, the total amount of feces varies greatly, it mainly depends on the dietary fiber content in the recipe. The more dietary fiber in the diet, the greater the amount of feces; the less dietary fiber, the smaller the amount of feces. Japanese author Gwangoka Contentment''s "Intestinal Revolution" (Hainan Publishing House) introduced a method for measuring the weight of feces with bananas: about 15 centimeters in length, a stool as thick as a banana, about 100 grams. It is common to excrete 1 or 2 roots a day, while many people have around 3 roots. Of course, everyone''s daily stool volume is not fixed.

The usual smell of feces is fecal odor. The components of the special odor during the formation period mainly include indole, hydrogen sulfide, skatole, amines, ammonia, acetic acid, butyric acid, etc. Among them, indole, hydrogen sulfide and skatole have the largest odor, which can be said to be unpleasant. Most of these odorous ingredients come from protein in food waste. In the large intestine, the proteins in the food that are not digested and absorbed by the small intestine will be decomposed and used by spoilage bacteria (yersinia, enterococcus, etc.) in the intestinal flora, and these odorous substances are produced at the same time.

　　The common causes of feces being too stinky are:

　　 1. Proteins in the diet, especially those containing more sulfur-containing amino acids, such as eggs and meat Excessive intake of similar products (soy protein is the opposite). Excessive intake leads to a decrease in protein absorption rate, causing more protein to enter the large intestine to be fermented by putrefactive bacteria in the intestinal tract, resulting in malodor.

　　 2. Constipation. Excessive retention of feces in the large intestine also enhances the fermentation of spoilage bacteria in the intestine, producing more odorous components.

　　 3. The elderly are aging. With the advent of old age, the power of bifidobacteria in the intestinal flora is declining, spoilage bacteria, etc. are rampant, and the absorption rate of protein (other nutrients are similar) is decreasing. Spoilage bacteria ferment protein, and feces will emit a smell that is even smellier than when they were young. This is the result of body aging.

　　 4. Occasionally, the stool may emit strange, uncommon odors, such as a pungent sour smell accompanied by diarrhea, which is often caused by abnormal fermentation (indigestion) in the intestine.