Black stool while taking antibiotics

Some medicines and foods can darken stool without bleeding, but colour alone cannot reliably identify the cause. Note whether the stool is jet black, unusually sticky, and strong-smelling, and report any accompanying symptoms.

Tarry black stool, called melaena, can occur when bleeding higher in the digestive tract is altered during digestion. Gastritis or a peptic ulcer can present this way. The antibiotic may be coincidental, or another medicine taken at the same time may irritate the stomach or increase bleeding risk.

Iron supplements and bismuth-containing remedies can make stool dark or black. That change is often not tar-like and may occur without dizziness, abdominal pain, or weakness. Greenish very dark stool can also look black in poor lighting, so checking in bright light may help describe it accurately.

Contact a clinician the same day for genuinely black or tarry stool. Share the antibiotic name, when treatment began, stool appearance, abdominal symptoms, and all other medicines or supplements. Mention pain relievers, blood-thinning medicines, iron, and indigestion remedies specifically.

Do not take an extra antibiotic dose to replace one you vomited, and do not start an anti-diarrhoeal or stomach remedy merely to hide the change. The prescriber can advise whether the antibiotic should continue while the cause is assessed. Keep hydrated unless a clinician has restricted your fluids.

Go to an emergency department or call UAE emergency services for black tarry stool with fainting, marked dizziness, confusion, shortness of breath, a racing heartbeat, severe or worsening abdominal pain, pale clammy skin, vomiting blood, or vomit resembling coffee grounds.

Arrange prompt assessment even if you otherwise feel well when tarry stool recurs. If a known darkening medicine explains the colour but the appearance changes or new symptoms develop, seek fresh advice rather than assuming the cause is unchanged.

Ask whether the stool could contain digested blood, whether any current medicine may irritate the stomach, and what evaluation is needed. Confirm which prescribed medicines to continue and what changes should trigger emergency care while awaiting results.