Bismuth Subsalicylate


Bismuth Subsalicylate is a commercial drug that is sold over the counter means it can be sold without any prescription. It has the chemical formula ${C_7H_5BiO_4}$. It was developed over 100 years back, in 1901, for the treatment and sanitation of cholera infection. First, in 1939 it was approved by FDA for the treatment of nausea, diarrhoea, and gastrointestinal infections. It is an insoluble salt of salicylic acid. It exhibits the property of antibacterial and antidiarrheal agents. It is used for the treatment of travellers' diarrhoea, nausea, stomach infection, antacid, heartburn, indigestion, etc.

What is Bismuth Subsalicylate

It is an insoluble salt of salicylic acid that is linked with a trivalent bismuth cation. A molecule of Bismuth Subsalicylate is composed of 58% bismuth and 42% salicylate by weight. It is also a component of HELIDAC Therapy i.e. (Bismuth Salicylate + Metronidazole + Tetracycline hydrochloride), that is used for the eradication of patients suffering from the H. pylori infection and ulcer. It is also known by the names Bismuth oxide salicylate, Pink Bismuth, Bismuth oxysalicylate, and Bismuth Subsalicylate.

Salicylic Acid

Salicylic acid is a beta hydroxy acid that is obtained from plants. It is a natural, odourless, white to light tan solid. It slowly dissolves in water or sinks in water. It has anti-inflammatory and antibacterial properties. It has exfoliating properties. The chemical formula of salicylic acid is ${C_7H_6O_3}$ or ${HOC_6H_4COOH}$. It is also known by the name 2-hydroxy benzoic acid, o-hydroxybenzoic acid, or 2-carboxy phenol. It is used for the treatment of acne, skin diseases, dandruff, seborrheic, dermatitis of the skin, common warts, corns, psoriasis, etc. It may also cause allergy-like peeling, dryness, redness of the skin, burning of the skin, etc.

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Salicylic Acid

Structure of Bismuth Subsalicylate

The molecular formula of Bismuth oxysalicylate is ${C_7H_5BiO_4}$. After the hydrolysis of pink bismuth, it changed into bismuth salicylate ${Bi(C_6H_4(OH)CO_2)_3}$. Let's see the chemical structure of bismuth oxysalicylate.

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Bismuth Subsalicylate

Physical and Chemical Properties

Bismuth subsalicylate is a white crystalline powder or white fluffy white solid. It has the following chemical and physical properties.

Physical Properties

AppearanceCrystalline or Fluffy Solid
Molecular formula$${C_7H_6BiO_4}$$
Molecular Weight363.10
Melting Point>350°C
Density${0.43 g/cm^3}$
Average mass362.093 Da

Chemical Properties

It has the following chemical properties.

  • Solubility: It is soluble in water and alcohol, but soluble in acids and alkali solutions.

  • The reaction of Bismuth Subsalicylate with hydrochloric acid: When bismuth subsalicylate reacts with hydrochloric acid it forms, 3,5-dihydroxybenzoic acid and bismuth chloride.

$${C_7H_5BiO_4+HCl\rightarrow C_7H_6O_4+BiCl}$$

  • It is decomposed by boiling water.

What is Bismuth Subsalicylate Used for?

Pepto-Bismol a brand name for bismuth subsalicylate, is used for the treatment of many gastrointestinal infections. It is the only bismuth salt that is allowed to sell over the counter. Let's see the uses of bismuth salicylate.

  • It is used to treat travellers' diarrhoea.

  • It is used for treating indigestion, diarrhoea, heartburn, nausea, and stomach infection, peptic ulcer.

  • It is used to treat the infection caused by Helicobacter pylori.

  • It reduced the prostaglandin formation by inhibiting the cyclooxygenase which induces inflammation and hypermotility.

  • It helps in the reabsorption of sodium, chlorides, and fluids.

  • It inhibits intestinal secretions.

Advisable Precautions and Dosage:

Although it has no side effects overconsumption of bismuth subsalicylate can result in nausea and black stool.

  • It can lead to the blacking of the tongue, teeth, fatigue, and mood changes.

  • In severe cases, it can cause mental disorders or neurotoxicity.

  • Other adverse effects are hearing loss, muscle spasms, headaches, and slurred speech.

  • If you are allergic to aspirin, salicylates, ibuprofen, naproxen, or celecoxib (NSAIDs) then it may cause allergic reactions and other issues.


Although it is an OTC drug, still has many side effects, so read the instruction carefully first or consult your doctor before the dosage of bismuth subsalicylates.

  • If it is in suspension form shake it before use.

  • If it is in chewable tablet form then swallow it.

  • Do not take more than 8 doses of this medicine in a day.

What Medicines Contain Bismuth?

Bismuth is used extensively as medicine for the treatment of diseases like gastrointestinal ailments, diarrhoea, etc. It also has anti-microbial, anti-cancer, and anti- leishmanial properties. Here is the list of a few medicines in which bismuth is used as an active compound.

Drug NameUses


Used for the treatment of Gastritis, and Dyspepsia.

Colloidal Bismuth Subcitrate CBS (De-Nol)

Used for Treatment of Ulcer

Pylorid (Ranitidine Bismuth Citrate, RBC)

For the treatment of H. pylori infections.

Bismuth Subnitrate Bismuth Subgallate

Used as antacid is used to Deodorise flatulence and in surgery of haemostasis.


In the above tutorial, we have studied that bismuth subsalicylate is an insoluble salt of salicylic acid. It is a colourless, odourless, white crystalline solid. It is widely used as a clinical drug for treating various diseases like gastric infections, diarrhoea, nausea, heartburn, etc. It has anti-bacterial, anti-cancer, anti-microbial, and anti-fungal properties. It is also used for the treatment of syphilis. It is used as a component in medicines like Bismuth subgallate, bismuth subnitrate, pylorid, Pepto-Bismuth, etc. Although it is a counter drug and is widely used without prescription still has many side effects like dark stool, darkening of teeth, and tongue minor and in severe cases, it can cause mental disorders, blurred vision, fatigue, muscle spasm, etc.


Q1. What does Pepto-Bismuth do?

Ans. It decreases the flow of fluids and reabsorbs sodium and other electrolytes in the intestine. It kills the bacteria causing diarrhoea.

Q2. How much dosage of bismuth subsalicylate is given in diarrhoea?

Ans. For a child of age between 6 to 8 around 2 to 3 tablets or 10 ml to 15 ml dosage is given. For an adult, 2 tablets or 30 ml dosage is given. Although doctors write doses for children but still not recommended for children below 12 ages.

Q3. Is bismuth subsalicylate given with other medicines?

Ans. It does not give with other medicines as it reacts with some medicines like aspirin, and aspartame, so it is recommended to consult with a doctor before taking this medicine.

Q4. What happens if you take too much dose of Pepto-Bismol?

Ans. If you have taken an overdose of Pepto-Bismol, it can cause various side effects like fatigue, buzzing in the ears, muscle spasms, mental confusion, etc.

Q5. How Pepto -Bismol works in the gastrointestinal tract?

Ans. In the stomach, the Pepto-Bismol reacts with hydrochloric acid and forms bismuth oxychloride and salicylic acid. This salicylic acid is absorbed in the body quickly and bismuth oxychloride is excreted with faeces.

$${C_7H_5BiO_4+HCl\rightarrow C_7H_6O_4+BiCl}$$


  • Bismuth Subsalicylate Oral: Uses, Side Effects, Interactions, Pictures, Warnings & Dosing - WebMD. (2022). Retrieved 19 July 2022, from:

  • Dajani, E., Thomas G. Shahwan (2004), in Encyclopedia of Gastroenterology, Retrieved 19 July 2022, from:

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Simply Easy Learning

Updated on: 13-Oct-2022


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