Bismuth subsalicylate - C7H5BiO4

What is Bismuth subsalicylate?

Bismuth subsalicylate is an active antacid with the chemical formula C7H5BiO4 under the brand name Pepto-Bismol. Bismuth subsalicylate is an insoluble bismuth salt widely used in the treatment of syphilis. It is slowly and irregularly absorbed but is an effective agent. Bismuth subsalicylate is an bismuth salt with a variety of clinical uses. Bismuth is an antidiarrheal agent that produces antisecretory and antimicrobial effects; it may have an antiinflammatory effect.

Other name – sic bismuth salicylate, salicylic acid basic bismuth salt


Bismuth subsalicylate



Molecular Weight/ Molar Mass

362.093 g/mol

Trade name


Melting Point

350 °C

Chemical Formula


Bismuth subsalicylate Structure – C7H5BiO4

Bismuth subsalicylate Structure

Physical Properties of Bismuth subsalicylate – C7H5BiO4


No odour


White powder



Vapour Pressure

603 and 638°C

Hydrogen Bond Donor



Practically insoluble in water or alcohol; soluble in alkali

Chemical Properties of Bismuth subsalicylate – C7H5BiO4

  • Bismuth subsalicylate reacts with hydrochloric acid results in the formation of 3,5-Dihydroxybenzoic acid and bismuth chloride.
  • C7H5BiO4 + HCl → C7H6O4 + BiCl

  • It forms microscopic prisms mat are decomposed by boiling water and by alkalies into a more basic salts.

Uses of Bismuth subsalicylate – C7H5BiO4

  • Used as a fungicide, especially for the control of blue mold disease of tobacco seedlings.
  • Used in the treatment of syphills and it may still be used in patients who are intolerant to penicillin.
  • Used orally to allay diarrhea or to soothe gastritis or peptic ulcer.
  • Used for symptomatic treatment of diarrhea in small and large animals.

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