Black stool is not always an indication of a serious medical problem. Diet and medications can turn bowel movements a very dark color. However, some medical conditions also have this symptom, and individuals should be aware of their stool color and consistency and note any significant changes, as this can facilitate prompt diagnosis and treatment.

Causes of Black Stool

Food can play a big part in stool color. Products containing black dye may cause the stool to turn black, including cupcakes with black frosting, or Oreo cookies. Certain medications or over-the-counter drugs can also cause a color change, especially iron pills.

Other Causes of Black Stool

If stool is black for several days and has a fouler odor than usual, a medical issue could be the cause. Some common conditions that can cause this symptom are ulcers in the esophagus or stomach, or gastritis. The blood lost due to these conditions mixes with stool and causes the discoloration. Blood in the stool is detected with a stool test.

Other Medical Reasons for Black Stool

Besides gastritis and ulcers, other medical conditions can cause black stool. As a general rule, bleeding from the upper half of the digestive tract will cause dark stools, while stool containing fresh, red blood are suggestive of bleeding in the lower part of the GI tract. Some cancers, such as stomach or esophageal cancer, also present with black stool in the early stages.

Other Traits of Black Stool

A considerable amount of blood or food dye is required to turn stool black. The stool may have other abnormal characteristics as well, including a strong, foul smell and may be sticky or tar-like in texture. Stool tests and other investigations will help the doctor find the underlying cause of black stool.

Black Stool in Newborns

When babies are first born, they will have black stool followed by a series of dark green bowel movements called meconium. This may last a couple of days but is normal. These meconium stools consist of amniotic fluid, mucus, lanugo (the fine hair that covers the body of the baby), bile, and cells from the skin and digestive tract.

Bismuth

Bismuth-based medications like Pepto-Bismol are sometimes used to treat digestive problems, and can make the stool to turn black. When bismuth combines with sulfur in saliva or the gastrointestinal tract, it becomes black. However, this is only temporary and not a sign of any serious medical condition. If rest, fluids, and bismuth products do not correct digestive issues in a few days, or if the stool remains dark after bismuth-based drugs are discontinued, it is best to see a doctor.

Ulcers

Ulcers are small internal sores that develop in the stomach, small intestine, or esophagus. When an ulcer becomes irritated or bursts, it can cause internal bleeding. When this occurs in the digestive tract, the blood that passes through the small intestine and mixes with feces can make subsequent bowel movements black.

Esophageal Varices

Esophageal varices is a medical condition caused by abnormal veins in the esophagus. If the veins become irritated, they may begin to bleed. The blood is digested and travel through the digestive system, eventually being excreted, which will turn the stool black. Esophageal varices require medical attention, and a doctor may prescribe medications or procedures to address the problem.

Necrotizing Enterocolitis

Necrotizing enterocolitis is a life-threatening condition caused by infection and inflammation of the intestine. It affects infants, and premature babies are more likely to develop it. Symptoms include dark or bloody stools, a swollen belly, chills and fever, and fast heartbeat and breathing. This condition requires hospitalization and treatment as soon as possible.

When To See a Doctor

The first thing one should do when they pass black stool is to determine whether any foods or drinks might have caused the occurrence. If one continues to pass black stool for multiple days or if pain or cramping accompanies bowel movements, the individual should seek medical attention.