Nausea and black stool: what you should know

Stool caused by digested blood may look black, sticky or tar-like and can have a strong smell. Bleeding may arise from irritation or an ulcer in the stomach or the first part of the small intestine. Gastritis is one possible cause, while medicines such as anti-inflammatory painkillers can also irritate the stomach.

Not every dark stool contains blood. Iron supplements, bismuth-containing stomach remedies and some dark foods can change stool colour. These explanations do not safely rule out bleeding, especially when nausea occurs with weakness, upper-abdominal discomfort or light-headedness.

Arrange urgent medical advice today and describe the colour, texture and number of dark stools. Take or photograph the packaging of any medicines or supplements you use, including painkillers, blood thinners, iron or stomach remedies. Do not take additional anti-inflammatory painkillers unless a clinician tells you to. Sip fluids only if you can keep them down, and avoid alcohol.

A clinician may check your circulation, blood count and abdomen, then decide whether further testing is needed. Do not drive yourself if you feel faint or unusually weak.

Call emergency services or go to an emergency department now if you vomit blood or material resembling coffee grounds, pass repeated black stools, faint, feel confused, have severe abdominal pain, develop cold clammy skin, or cannot keep fluids down. These signs can indicate significant blood loss or dehydration.

Seek urgent assessment even without these warning signs if the stool is genuinely tar-like, if you take a blood thinner, or if the dark stool continues. Bring a list of medicines and any relevant medical records.

Ask whether the stool appearance could represent digested blood, whether any medicine should be paused or changed, and which symptoms should prompt immediate return. Mention recent vomiting, indigestion, abdominal pain, alcohol use, previous ulcers, liver problems, and every prescription, over-the-counter medicine and supplement.