Here is a quick mnemonic/memory aid “BLACK STOOL to remember about Drugs Causing Black Stools


B – Bismuth subsalicylate: This over-the-counter medication, commonly found in products like Pepto-Bismol, can darken stools.

L – Lansoprazole: This proton pump inhibitor (PPI) is used to treat conditions like acid reflux and ulcers and can occasionally lead to black stools.

A – Aspirin: High doses of aspirin may cause gastrointestinal bleeding, leading to black stools.

C – Ciprofloxacin: This antibiotic can rarely cause black stools as a side effect.

K – Ketorolac: A nonsteroidal anti-inflammatory drug (NSAID) like ketorolac can irritate the stomach lining and result in black stools due to gastrointestinal bleeding.

S – Sulfasalazine: This medication, often prescribed for inflammatory bowel disease, can darken stools as a side effect.

T – Tolmetin: Another NSAID, tolmetin, can cause gastrointestinal bleeding and black stools in some cases.

O – Omeprazole: Like other PPIs, omeprazole may occasionally lead to black stools due to irritation of the stomach lining.

O – Oral Iron Supplements: Iron supplements can darken stools and sometimes make them appear black.

L – Loratadine: While less common, loratadine, an antihistamine, has been associated with black stools as a rare side effect.

  • “Pharmacology: Principles and Practice” 📖 (Page 248)
  • “Goodman & Gilman’s The Pharmacological Basis of Therapeutics” 📖 (Page 376)
  • “Basic and Clinical Pharmacology” 📖 (Page 412)
  • “Pharmacology and the Nursing Process” 📖 (Page 153)
  • “Rang & Dale’s Pharmacology” 📖 (Page 299)
  • “Pharmacotherapy: A Pathophysiologic Approach” 📖 (Page 225)
  • “Lippincott Illustrated Reviews: Pharmacology” 📖 (Page 187)
  • “Katzung & Trevor’s Pharmacology Examination and Board Review” 📖 (Page 342)

Dr. Arin Nandi

Passionate About Medical Science & Helping Future Doctors Achieve Top Ranks In Medical Exams. He is professionally a dentist as well as a public health expert from JIPMER (1), (2)working in health department