Black bits in stool: possible causes

Pepper-like flecks can follow dark foods, seeds or skins that were not fully broken down. Iron and bismuth can darken bowel contents. Blood from higher in the digestive tract is more often spread through stool and may make it black, sticky or tar-like, rather than appearing as a few clearly separate pieces. Gastritis, peptic ulcer disease and Helicobacter Pylori Infection are possible upper digestive causes. A single observation cannot establish which explanation applies.

Think back over recent meals and check the labels of supplements and medicines. If safe and practical, take a clear note of the appearance rather than repeatedly inspecting stool. Arrange medical advice if the change recurs, the entire stool becomes black, or you also have upper abdominal discomfort, unusual tiredness or reduced appetite. Do not discontinue prescribed medicines on your own.

Seek urgent care for fainting, dizziness when standing, weakness that is getting worse, severe abdominal pain, vomiting blood or coffee-ground material, or black tarry stools. Emergency assessment is particularly important if you use blood thinners or anti-inflammatory painkillers.

Ask whether your medicines, supplements or diet could explain the flecks, what features would suggest melaena, and whether examination or testing is needed if the change returns.