Spinach and black stool: what it may mean

Leafy greens may change stool colour through their pigments, particularly after a large serving, and the change should fade as digestion returns to your usual pattern. Black stool that looks shiny, sticky or tarry is different from dark green stool. It can indicate digested blood from higher in the digestive tract. Gastritis, Helicobacter Pylori Infection and Peptic Ulcer can irritate or damage the stomach or duodenal lining and may cause this type of bleeding. Iron or bismuth medicines can also darken stool, so list every medicine and supplement you take.

Look at the stool in good light and note whether it is green-dark, brown-dark or tarry. Record what you ate, when the colour changed, and any medicines or supplements. Do not stop prescribed medicine without advice. If the stool is genuinely black or the change repeats, contact a clinician promptly even if spinach was recently eaten; an examination and stool or blood assessment may be needed.

Go to urgent care for black tarry stool with dizziness, faintness, unusual weakness, shortness of breath, vomiting blood, severe abdominal pain or a fast heartbeat. These symptoms can accompany significant digestive bleeding. Seek same-day advice for repeated black stools, especially if you have a history of ulcers, take blood-thinning medicine or feel unwell.

Does the colour look more like food pigment or digested blood? Could my medicines or supplements explain it? Should I be checked for an ulcer, gastritis or Helicobacter Pylori Infection? What symptoms should prompt emergency care?