The Chemistry of Pepto Bismol


  • I chose to do the chemistry of Pepto Bismol. I chose this because I wanted to learn how and why Pepto Bismol works inside the body. Pepto Bismol is a brand name product for a medicine called Bismuth Subsalicylate. Bismuth Subsalicylate is used to treat upset stomach, diarrhea, indigestion, heartburn, and other minor stomach ailments.Composition of ...
    • Bismuth subsalicylate
      • chemical formula C7H5BiO4
        • 7 carbon, 5 hydrogen, one bismuth, 4 oxygen
        • the actual structure is unknown formula is just approximate
        • molecular weight of is 363.100 g/mol
        • bismuth salt
        • medical ingredient in pepto bismol
    • Benzoic acid
      • Chemical formula: C7H6O2
      • important ingredient in organic substances
      • occurs naturally in many plants
    • magnesium aluminum silicate
      • Used in many skin care products
    • methylcellulose
      • can be used to treat constipation because it can’t be absorbed by the intestines but attracts water to the colon
      • also many other uses ranging from construction products, consumer products, and medical uses such as artificial tears and saliva.
    • sodium saccharin
      • artificial sweetener used in food products, 300-400 times as sweet as sucrose (table sugar)
    • salicylic acid
      • reduces inflammation and irritation in the stomach and intestinal linings
      • Chemical formula C7H6O3
    • sodium salicylate
    • sorbic acid
    • water

Main Chemicals, Compounds, Components

The main ingredients of Pepto Bismol are Bismuth and Benzoic acid.


    • atomic number 83
    • 208.98 atomic mass
    • may occur naturally
      • white/ silver brittle heavy metal.
      • poor conductor of electricity for being a metal
      • low toxicity for being heavy metal also.
    • used in pepto bismol

Benzoic acid

    • chemical equation
    • C7H6O2
    • occurs naturally in many plants’
    • salt used in food preservatives

Chemistry's Role

It is not know exactly how the pepto bismol reacts inside the stomach. Pepto bismol“Coats” the irritated tissues to calm down the explosive fluids inside the stomach. It also combines to the toxins produced by E.coli preventing forms of travelers diarrhea. Another reaction inside the stomach that take place is called the oligodynamic effect. The oligodynamic effect is when small amount of a heavy metal, in this case bismuth, is used to kill some of the harmful microbes inside the stomach. It reduces the secretion inside the digestive tract calming the stomach. One ingredient Salicylic acid is known to reduce the irritation and inflammation inside the stomach and intestines. It is due to the combination of these reactions that help the symptoms disappear.

Background Research

Pepto was first made in the early 20th century. It was created by a doctor inside of his own home looking for a cure to the widespread disease of cholera. After his medicine became a hit and he could not manufacture enough inside his home he brought his recipe to a pharmacal company in New York. The name was then changed to its currents name in 1919 Pepto Bismol to help appeal to the adult population more. Although the main purpose is no longer needed it now is used for other stomach problems such as indigestion, diarrhea, nausea, and heartburn.


this website is directly from the company and tells very general background information of the product

this website has tons of information of almost everything about pepto bismol

more information on the ingredients and how its pepto bismol works and the ingredients of the original liquid

this website has information on antacids and how they work with the stomach to combat nausea and other stomach ailments.

this website has tons of information on BISMUTH SUBSALICYLATE including structure and many other chemical properties

also directly form the company explaining why it may turn stools and tongue black and why that is harmless

This website contains information on why this medication is used and contains warning for usage

About the Author

Andy Maehl is a junior at senior high. He enjoys not only watching but playing sports. He plans to attend Montana State but is undecided on what to study. He is a member of the varsity football team at Billings Senior High School that placed second in state during the 2015 season.