What is the reason for the change of stool color?

Stool color can be changed for many reasons This change reflects a change in the substance in the stool Some stool color changes are related to the intake of specific food or drugs, but some indicate that there are problems in the body, which should be paid attention to Black stool (not sticky, tasteless) causes of black stool include taking iron health products or bismuth containing drugs (such as bismuth salicylate or pepto Bismol) But if the black stool is caused by these drugs, it is usually not sticky and does not smell bad Black sticky stool stomach (gastritis or gastric ulcer) or intestinal bleeding can make the stool this color If the bleeding occurs in the stomach or in the upper part of the small intestine, the stool will become black and sticky, which is described in medical terms as meconiosis Tar black stool usually has a bad smell This change in color and viscosity can be caused by blood chemistry in the gut, which is related to digestive enzymes in the gut Chestnut or red stool if the bleeding is from the intestine or the lower part of the colon, the blood may not be able to keep in constant contact with digestive enzymes because it is too close to the bleeding point of the colon In addition, a large amount of blood in the intestine will accelerate the transfer of feces, so there is not much time for transformation This type of bleeding can turn the stool black or chestnut In addition, eating beets, other red vegetables, cranberries and red food dyes can also turn your stool red or chestnut If there is no bile or a small amount of it, it will become gray or clay Gray may mean that bile flow to the intestine is blocked, such as bile duct infarction due to tumor or nearby pancreatic stones This color change usually evolves with the development of the disease The Yellow stool may be due to the presence of undigested fat in the stool This is usually the result of a decrease in the enzymes that are delivered to the digestive tract as a result of pancreatic disease, such as the release of digestive enzymes from the pancreas and their passage into the intestine, which is important to help digest fats and other food ingredients If the pancreas can't transfer the enzyme to the intestine, the food ingredients (especially fat) will be difficult to digest and absorb Feces containing undigested fat will turn yellow, greasy and stinky Weight loss drugs such as orlistat work by limiting the amount of fat absorbed by the gut This can cause yellow greasy stools In addition, eating extremely high-fat foods can also cause yellow and smelly stools When the green stool passes through the intestine quickly (diarrhea), bilirubin does not have enough time for normal chemical reaction, so it will make the stool green In addition, eating too much green or food dye (green or purple) food and vegetables will also cause the stool color to turn green.