Pepto-Bismol is used to treat indigestion, stomach upset, nausea, diarrhea and other conditions that are associated with eating excessively. A doctor may also prescribe it for other conditions, as stated by Drugs.com. As of 2014, it is still not understood how Pepto-Bismol works, but it is believed that it inhibits secretions in the digestive tract.
A person who has fever or mucus/blood in the stool should not use this drug to treat diarrhea. Those people who are allergic to any ingredients of the drug or who have bleeding problems are advised not to use Pepto-Bismol. Pregnant women, diabetes patients and people using other medications should talk to a health care provider before taking this medication. Pepto-Bismol can be taken with extra fluids and with or without food. It should be taken as directed unless instructed otherwise by a doctor.
A common side effect of using Pepto-Bismol is the darkening of the stool or tongue. This can be temporary or permanent. Severe side effects due to allergy or reaction of Pepto-Bismol with other drugs in the body can also occur. These effects include fever, vomiting, nausea, swelling and hearing loss, as stated by Drugs.com. Following the doctor's instructions helps to avoid such effects.