Bismuth Subsalicylate Side Effects Dosage and Uses

It is a white solid practically insoluble in water.

Its main use is for the treatment of some diseases of the digestive tract, a use that began to be applied at the beginning of the 20th century.

It is administered orally and when it reaches the stomach, the gastric juices break it down into a salt of bismuth and salicylic acid. Both compounds act on digestive disorders.

As early as 1799, medical therapies for gastrointestinal diseases using bismuth salts were known in Europe. Based on this knowledge, in the first decade of the 1900s, mixtures of bismuth subsalicylate with other compounds were used to treat a type of infant diarrhea.

Structure of Bismuth subsalicylate

Bismuth subsalicylate has two rings in its structure: an aromatic ring made up of carbon atoms joined together by double bonds and, attached to this, a ring made up of two oxygen atoms, one carbon, and one bismuth.

Bismuth is also attached to an -OH group.

Structure of Bismuth subsalicylate
Chemical structure of bismuth subsalicylate. Edgar181 / Public domain. Source: Wikimedia Commons.

Nomenclature of Bismuth subsalicylate

  • Bismuth subsalicylate
  • Bismuth Oxisalicylate
  • Bismuth Salicylate Oxide
  • Pink bismuth (from English pink bismuth )

Properties of Bismuth subsalicylate

Physical state

  • White crystalline woolly solid. Crystals in the form of prisms.

Molecular weight

  • 362.093 g/mol


  • Insoluble in water and alcohol. Soluble in acids and alkalis. Insoluble in ether. Soluble in oil.

Other properties

  • The alkalis make it a more basic salt. With hot water, it decomposes. It is stable if exposed to air but is affected by light. It has no smell or taste.


It is prepared by hydrolysis of bismuth salicylate (Bi (C6H4(OH) COO)3).

Applications of Bismuth subsalicylate

It is used in the treatment of some stomach diseases and various gastrointestinal symptoms. It has anti-inflammatory properties, acts as an antacid, and has a bactericidal effect.

In mild gastric problems

It is used to treat nausea, upset stomach, indigestion, a burning sensation in the stomach and esophagus from heartburn, dyspepsia, and to soothe mild gastritis.

Applications of Bismuth subsalicylate
Commercial drug containing bismuth subsalicylate. User: Chemicalinterest / Public domain. Source: Wikimedia Commons.

For stomach ulcer

Doctors use it together with other medications in the treatment of gastric ulcers, always under supervision. This is because it is effective against Heliobacter pylori bacteria.

For stomach ulcer
Stomach ulcers can be treated with bismuth subsalicylate. Author: Anastasia Gepp. Source: Pixabay.

In addition, it is estimated that it plays an important role in preventing the recurrence of this disease.

In intestinal problems

It is used to relieve mild diarrhea or acute diarrhea and other transient digestive tract problems. It acts as an intestinal absorbent.

In travelers’ medicine luggage

It is useful to avoid contracting traveler’s diarrhea or reduce its severity. It helps reduce the number of bowel movements and shorten the duration of the condition.

The protection is 65% but after about 3 weeks the effect diminishes rapidly.

In other therapeutic methods

Before the discovery of penicillin, it was widely used in the treatment of syphilis. It was also used to cure ulcerative gingivitis, which is a strong bacterial infection of the gums.

It was also used as a suppressant for lupus erythematosus, a disease of the immune system that consists of attacking the body’s own cells.

In veterinary applications

It also serves as an antidiarrheal in animals. It acts as a mild intestinal antiseptic due to the release of salicylic acid. It is combined with carbonates to minimize irritation from free stomach acid, while bismuth exerts a protective effect.

In veterinary applications of Bismuth subsalicylate
Cats can be poisoned by bismuth subsalicylate. Author: Croisy. Source: Pixabay.

However, above certain doses it can be toxic to animals, especially cats.

Action mechanisms

Bismuth subsalicylate hydrolyzes in the stomach, as it reacts with hydrochloric acid (HCl) to form bismuth oxychloride (BiOCl) and salicylic acid or 2-hydroxybenzoic acid (C 6 H 4 (OH) COOH), which generates salts salicylate.

Effects of salicylate

Salicylate is rapidly absorbed by the body, but it is believed to decrease intestinal secretion, reducing the frequency of evacuation and its liquidity.

Effects of bismuth

Bismuth is believed to exert its therapeutic action in part because it stimulates prostaglandins, which are lipid-derived compounds that have various functions in the body.

In addition, bismuth favors the formation of mucus and the secretion of bicarbonate. Coats gastric ulcers, protecting them from stomach acid and pepsin.

It also has a direct antimicrobial effect and chemically binds to enterotoxins produced by bacteria, deactivating them. It also interferes with the adhesion of microorganisms to the cells of the intestinal mucosa.

Bismuth acts as an antibacterial in the intestine. Author: OpenClipart-Vectors. Source: Pixabay.

Its antibacterial action is modest against Escherichia coliSalmonella spp, and Campylobacter jejuni. Sometimes it allows the eradication of the Helicobacter species.

Contraindications of Bismuth subsalicylate

During pregnancy or breastfeeding

Bismuth subsalicylate should not be administered during pregnancy or lactation.

Although bismuth has not been reported to cause abnormalities in human fetuses, chronic administration of bismuth tartrate has been associated with unsatisfactory results in animal studies.

On the other hand, chronic ingestion of salicylates during pregnancy can lead to fetal malformations and damage to the mother’s uterus.

Patients taking other medications

The salicylate that this compound generates is easily absorbed, so attention should be paid to people who are taking aspirin (acetylsalicylic acid) or other medicines that contain salicylates, since toxic levels of these can be reached in the body.

This recommendation is also valid if they are taking anticoagulants such as warfarin or non-steroidal anti-inflammatory drugs.

People who are prescribed antibiotics should not take bismuth subsalicylate, because it decreases the absorption of the antibiotic; Nor if they are taking doxycycline to prevent malaria (travelers), as its bioavailability decreases.


Products containing this compound should not be used in children under 12 years of age, because there are not enough studies to prove its effectiveness and lack of harm in minors.

Also, when children have viral infections like chickenpox or influenza, taking bismuth subsalicylate puts them at risk for Reye’s syndrome, the effects of which include liver damage and mental confusion.

Patients with kidney problems

It is contraindicated for patients with kidney failure.

Collateral damage of Bismuth subsalicylate

Consequences such as nausea, vomiting, and tinnitus (sounds or buzzing within the ear that have no external origin) have been reported.

Causes darkening or greenish-black discoloration of the tongue and stools. This is due to the formation of bismuth sulfide (Bi2S3) by the reaction of the element with sulfides produced by bacteria in the digestive tract.

May interfere with radiological studies of the gastrointestinal system. Bismuth salts are not appreciably absorbed from the stomach or intestines, however, their prolonged use is not recommended because this element can be neurotoxic.

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