What should you know about black green stool causes?

Causes include dark food pigments, green vegetables, iron supplements and medicines containing bismuth. Rapid movement through the bowel can leave more bile in stool, giving it a green shade. Black, sticky stool can form when blood is digested higher in the digestive tract. Gastritis, Helicobacter pylori infection and peptic ulcer are conditions a clinician may consider, particularly when there is upper abdominal discomfort, nausea or a history of ulcer symptoms. The symptom does not identify one diagnosis by itself.

Write down recent foods, supplements and medicines, and take a photograph only if it can help describe the change safely. Keep hydrated if loose stools are present. Contact a clinician about unexplained black stool or a change that persists. Never alter prescribed treatment without professional guidance.

Get urgent care if stool is tar-like or repeatedly black, or if you have vomiting blood, coffee-ground vomit, faintness, confusion, unusual weakness, breathlessness, a fast heartbeat or severe abdominal pain. Those features can accompany significant digestive bleeding.

Ask which cause fits the timing, whether your medicines should be reviewed, and whether blood or stool testing is appropriate. Tell the clinician about pain, vomiting, dizziness and any previous stomach or bowel condition.