Although it is an uncommon color for poop, it is not exactly impossible for blue poop to occur. The reasons may vary depending on the situation, but mostly the reasons are related to the consumption of something earlier to the particular bowel movement. Unfortunately though, there are also certain diseases that could be responsible for a bluish green color. The good news however is, if poop is blue without being greenish in any way, then the chances are that the reason is not a disease or disorder, because blue poop is generally not associated with any disease. Both the type of reasons will be discussed at length in the paragraphs below.

What causes poop to turn blue?

1. Prussian blue -– An established reason behind the appearance of blue poop is the indirect consumption of pigments and Prussian blue is one of those pigments. Prussian blue capsules are also used to treat patients who are suffering from radiation poisoning, cesium poisoning or thallium poisoning. As the chemical (Fe7(CN)18) is actually a dye, patients who have been administered a significantly high dosage of Prussian blue capsules might excrete blue poop until the pigment is out of his/her system.

2. Artificial coloring in food and drink items -– Edible dyes are the most common reasons behind the appearance of blue poop as they are present in so many of the foods and drinks that are available today. Some of the common items, consuming which can turn one’s stool blue include Kool Aid, grape soda, blue curaçao, colored candy, ice-cream etc. Blue velvet cakes are found to be exceptionally effective in turning one’s poop bright blue due to the high content of indigestible dye content in them. Although it has no directly harmful effects, all health persons advise against consuming too much of these artificial colors.

3. Baby formulas -– Babies are known for excreting stools of different colors and in most of the cases, it is nothing to worry about. The blue poop is normally the result of the baby formula that the baby is being fed at the time. Consumption of the same formula may not give all infants blue poop though. It is the ongoing formation of the infant’s digestive system that makes the child poop in colors which are similar to what he/she is fed.

4. Consumption of inedible colors -– Small children and mentally challenged individuals may at times consume colored items like glitters, crayons or colors and that could be a reason behind the occurrence of blue poop. While crayons, playdough and other types of colors are not really known to harm anyone seriously, the glitters on the other hand can cut the insides of one’s digestive system as they are actually metal shards. In any case however, if anyone is experiencing blue poop on the account of consuming anything inedible, that person should receive immediate medical attention.

5. Blueberries -– Blueberries contain natural blue pigment in them and if one consumes a significant amount of blueberries within a short time, there is a good chance that the person might see blue poop the next time he/she has a bowel movement. The amount of blueberries that it would take to turn a person’s stool blue will differ from person to person though. This is a harmless phenomenon and the color will pass soon enough.

6. A diet rich in fat and protein -– It has been observed that if someone follows a diet which is unusually rich in fat and protein (meat, eggs etc), the person’s stool may turn dark olive blue. The color is brought on due to excessive bacterial action on the food items during the process of digestion. This kind of blue excreta is usually accompanied by a strong foul smell as well. It may cause gas and reducing the intake of fats and proteins, at least on a temporary basis can be helpful.

Is it blue or green?

There are a lot of reasons that could be responsible for the occurrence of green poop and some of them are quite serious. At times, the green excreta may appear blue/bluish green and thus it can be mistaken for blue poop. The diseases that are mostly associated with bluish green/greenish blue poop include diarrhea, Irritable Bowel Syndrome, Crohn’s disease, celiac disease, bacterial overgrowth etc. Vegetables rich in iron and iron pills are also associated with turning the color of one’s poop green; but as mentioned before, it may appear bluish from time to time. While the bluish green color from the unabsorbed iron (from the iron pills and vegetables) should not worry anyone, medical attention would be necessary if the cause of the unusual color is one of the diseases mentioned above.





How to prevent it?

Preventing the occurrence of pure blue poop is not as important as it is to prevent the occurrence of some of the other unusual colors that are seen sometimes during a bowel movement. This is true because medical science does not associate the color blue with any serious disease or disorder.

Nonetheless, the unexpected color can be discomforting for some and for them, the advice is to stay away from foods and drinks that contain artificial colors. If the person in question is not a mature adult, then it is highly advised that he/she is kept under strict supervision in order to prevent the person from eating inedible colors. In general, it is safe to say that that keeping all things mentioned above, off the menu is a more or less sure shot way to prevent blue poop. When it comes to babies and blue poop induced by their vitamin intake, it is an absolutely safe and normal incident which does not need prevention.

Things would become a bit more serious however, if the actual color is mainly green as it can indicate a host of diseases. If you see any greenish tint in the poop, but cannot think of any artificial coloring that was consumed earlier, it is best to consult a doctor. Following a healthy lifestyle with a balanced diet, proper exercise and regular medical checkup increases the chances of good health and reduces the chances of digestive disorders.