Does Pepto-Bismol cause black stools? 

Does Pepto-Bismol cause black stools? 

Pepto-Bismol can make your stools appear black. This is considered a common side effect of this medication. The reason why that happens is that Pepto-Bismol contains Bismuth Subsalicylate – which can react with Sulphur present in your stomach. 

Now, the availability of Sulphur varies from person to person. As the common source of Sulphur is our diet, high sulphur-containing food in your stomach can increase the availability of this element and causes more Bismuth Subsalicylate to react with it (1). 

However, the end product of this reaction is Bismuth sulphide – which is black in colour. This end product can make your stool appear black or very dark in colour (1). 

Should you be concerned about black stools caused by Pepto-Bismol? 

Black stools caused by Pepto-Bismol are usually nothing to worry about. It’s just the colour that’s changed and there is no other physical difference caused by the reaction. So don’t get scared if your stool appears black. It will stop once you are done taking the medication. 

Side effects associated with long-term use of Pepto-Bismol

Long-term use of Pepto-Bismol can sometimes lead to certain side effects. It’s important to note that most people can safely use Pepto-Bismol for short periods without experiencing any significant issues. 

However, if used for an extended period or in excessive amounts, the following side effects may occur: (2)

Constipation

Some individuals may experience constipation as a result of using Pepto-Bismol for an extended period. This can cause difficulty passing stools or infrequent bowel movements. (2)

Stomach discomfort

Prolonged use of Pepto-Bismol may lead to stomach discomfort or an upset stomach. This can include symptoms like nausea, bloating, or an overall feeling of discomfort in the abdominal area. (2)

Reye’s syndrome (rare)

Although rare, long-term use of Pepto-Bismol in children or teenagers who have a viral infection, particularly the flu or chickenpox, may increase the risk of developing Reye’s syndrome (3). 

Reye’s syndrome is a severe condition that affects the liver and brain, so it is important to follow the recommended usage guidelines for Pepto-Bismol in children.

Salicylate toxicity (rare)

Chronic use of Pepto-Bismol can cause Salicylate toxicity in some individuals (4). 

When someone experiences salicylate toxicity, they may develop symptoms such as ringing in the ears, dizziness, rapid breathing, confusion, nausea, vomiting, and even more severe symptoms like seizures or loss of consciousness in severe cases (4). 

It’s important to note that salicylate toxicity can be dangerous and requires prompt medical attention.

Other potential causes of black stools

Other potential causes of black stools include:

• Consuming certain foods and medications: Foods like black liquorice, blueberries, or iron supplements can cause temporary black stools. 

• Gastrointestinal bleeding: Black stools can be a result of bleeding in the gastrointestinal tract. When blood is exposed to digestive enzymes, it undergoes changes and appears black. This type of bleeding may be caused by ulcers, gastritis, or bleeding in the upper digestive system. (5)

• Intestinal conditions: Certain intestinal conditions, such as diverticulitis or Crohn’s disease, can lead to black stools. These conditions can cause bleeding or changes in the digestive process, resulting in dark-coloured stools.

• Medications and supplements: Some medications, particularly those containing iron or activated charcoal, can cause black stools as a side effect. Always check the labels of your medications to see if black stools are listed as a possible side effect.

If you notice black stools and are unsure of the cause, it’s important to consult with a healthcare provider. They can evaluate your symptoms, and medical history, and perform any necessary tests to determine the underlying cause. 

Final words

To sum up, Pepto-Bismol can darken the colour of your stools – which is usually nothing to worry about. However, it is not recommended to take Pepto-Bismol for a prolonged time without your doctor’s approval. 

Furthermore, black stools can sometimes be a sign of a more serious underlying problem – which is why you should talk to your doctor about it and rule out any dangerous condition, like gastrointestinal bleeding. 

References