Diarrhea then black stool: what to know

True melaena is usually black, sticky or tar-like and may have a strong, unpleasant smell. Blood from higher in the stomach or small intestine can be altered during digestion, producing this appearance. Gastritis and a peptic ulcer are possible causes; Helicobacter Pylori Infection can contribute to ulcer disease. Iron tablets, bismuth medicines and some dark foods can also darken stool, but a sudden tarry change should not be self-diagnosed.

Contact a healthcare professional promptly and describe when the diarrhea began, how many dark stools you noticed, and whether the stool was sticky or tar-like. Bring or photograph the medicine packaging if you use iron, bismuth, aspirin or an anti-inflammatory painkiller. Drink small amounts of fluid if you can keep them down, but do not delay assessment to treat the diarrhea at home.

Seek emergency care now for faintness, confusion, severe weakness, vomiting blood or material resembling coffee grounds, severe abdominal pain, a fast heartbeat, or repeated black stools. These can accompany significant blood loss or dehydration. Children, older adults, pregnant people and anyone taking a blood thinner should seek advice urgently even when symptoms seem mild.

Could this be melaena or medicine-related darkening? Do I need blood tests or stool assessment? Which pain relievers should I avoid until the cause is clear? How should I replace fluids safely?