Why Does Soda Give Me Diarrhea?
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Why Does Soda Give Me Diarrhea?

Why Does Soda Give Me Diarrhea?
Everyday Health
By
Denise Mann, MS
Updated on July 31, 2025
by

Does drinking soda upset your stomach and cause diarrhea? If so, you’re not alone, says William J. Bulsiewicz, MD, a gastroenterologist based in Mount Pleasant, South Carolina, and the author of Fiber Fueled. A number of factors may lead to gastrointestinal symptoms after sipping a glass of cola. It can be helpful to know your triggers and what you might drink instead.

1. Caffeine

For starters, there’s the caffeine factor, Dr. Bulsiewicz says. “A handful of people with irritable bowel syndrome (IBS) will have an aggravation of their IBS when they consume caffeine,” he says. “They don’t tolerate caffeine well, and it will give them diarrhea.”

A common gastrointestinal disorder, IBS comes with symptoms that include constipation, diarrhea, abdominal pain, and bloating. The exact cause of IBS is unknown, but issues with the nervous system, severe infections, stress, and changes to the gut microbiome are thought to play a role.

Caffeine may also stimulate the intestines and increase motility, Bulsiewicz says. “Motility” refers to the movement that causes stool to travel through the digestive tract for elimination, he explains.

2. Sugar

Aside from caffeine, the amount of sugar in soda may also cause diarrhea. “If you overwhelm your body with sugar, you will get diarrhea,” Bulsiewicz says. Sugar-sweetened beverages, including sodas, are the top source of added sugar in the American diet.

Many sodas are sweetened with high-fructose corn syrup, a kind of processed sugar that’s less expensive and more shelf-stable than regular sugar.

 Some people have trouble digesting fructose, a condition called fructose malabsorption, which can cause bloating, stomach pain, heartburn, diarrhea, and gas.

Sugar comes in different forms with different names. To avoid it, read product labels carefully and keep away from products with:

  • Fructose
  • High-fructose corn syrup
  • Honey
  • Agave syrup
  • Invert sugar
  • Maple-flavored syrup
  • Molasses
  • Palm or coconut sugar
  • Sorghum

3. Artificial Sweeteners

Just because you go for diet sodas doesn’t mean you’re off the hook. “If you opt for diet soda, artificial sweeteners may be worse,” Bulsiewicz says. In some people, artificial sweeteners, which are created in a lab to taste sweet but contain no sugar, can have a laxative effect. “They pull water into the colon and help to mobilize the stool, which can cause the runs,” Bulsiewicz explains. Some people may get diarrhea after consuming large quantities of artificial sweeteners, while others may get gastrointestinal distress from even a small amount.

4. Carbonation

Another aspect of soda that may cause diarrhea is the carbonation that gives soda its fizz. This can create belching, flatulence, and indigestion. “It won’t cause irritable bowel syndrome, but if you are someone who is sensitive to carbonated beverages and you have IBS, the bloating and gas may cause a flare and lead to diarrhea,” Bulsiewicz says.

Alternatives to Cut Soda Consumption

It makes sense to avoid or limit the amount of soda you drink for many reasons, especially if it upsets your stomach and leads to diarrhea.

Research has linked the consumption of sugar-sweetened beverages like soda to an increased risk of a number of health conditions, including obesity, heart disease, type 2 diabetes, kidney disease, and liver disease.

Research has found that drinking no- or low-calorie drinks, such as water, unsweetened tea, and low-fat or fat-free milk, instead of sugary drinks, can help improve weight in both adults and children.

These are also better choices to ensure good hydration. The Academy of Nutrition and Dietetics recommends that women aim for about 11 ½ cups of water each day and men aim for about 15 ½ cups. These recommendations include water from both beverages and foods.

“If soda gives you diarrhea, ginger ale may be a better choice,” Bulsiewicz says. “If you get real ginger ale, it contains ginger, which has medicinal properties that can calm an upset stomach, and it is caffeine-free.”

Though unpleasant, diarrhea from soda is usually not dangerous, Bulsiewicz says. However, “if you have a change in bowel habits, see blood in your stool, and are experiencing weakness, fatigue, and unexplained weight loss, or if these symptoms are chronic and escalating, see your doctor,” he adds.

The Takeaway

  • Drinking soda can cause an upset stomach and diarrhea for a number of reasons, including caffeine and sugar content, the use of artificial sweeteners in diet soda varieties, and carbonation.
  • To avoid these unpleasant symptoms and to make choices that are better for your health, opt for no- or low-calorie drinks such as water and low-fat or fat-free milk.
  • While diarrhea from drinking soda generally isn’t dangerous, seek medical attention if you’re experiencing other symptoms along with it, including blood in your stool, weakness, and unexplained weight loss.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Irritable Bowel Syndrome. Mayo Clinic. October 11, 2024.
  2. Get the Facts: Sugar-Sweetened Beverages and Consumption. Centers for Disease Control and Prevention. April 11, 2022.
  3. What Is High Fructose Corn Syrup? And Why It’s Bad for You. Cleveland Clinic. April 1, 2025.
  4. Fructose Intolerance: Which Foods to Avoid? Mayo Clinic. January 9, 2024.
  5. Artificial Sweeteners and Other Sugar Substitutes. Mayo Clinic. January 10, 2023.
  6. 5 Foods to Avoid if You Have IBS. Johns Hopkins Medicine.
  7. Tobiassen P et al. Substitution of Sugar-Sweetened Beverages With Non-Caloric Alternatives and Weight Change: A Systematic Review of Randomized Trials and Meta-Analysis. Obesity Reviews. October 25, 2023.
  8. How Much Water Do You Need? Academy of Nutrition and Dietetics. May 17, 2024.
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Melissa Sleight, RDN

Medical Reviewer
Member of American College of Lifestyle Medicine
Melissa Sleight, RDN, is a board-certified lifestyle medicine dietitian with over 15 years of experience. She has a passion for educating her clients about improving their health through nutrition and lifestyle changes, and seeing them motivated to improve their health each day.

Sleight earned her bachelor's in nutrition and food science from Utah State University. She is a member of the American College of Lifestyle Medicine and the Sports, Cardiovascular, and Wellness Nutrition group for the Academy of Nutrition and Dietetics. She is involved at the local level as the president-elect of Magic Valley Dietitians and is a liaison for her community as a board member of the Idaho Academy of Nutrition and Dietetics.

She likes to cook and try new recipes, and loves water activities of all kinds — from paddleboards to hot tubs. She enjoys exploring the outdoors through hiking, on all-terrain vehicles, and camping.
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Denise Mann, MS

Author
Denise Mann, MS is a veteran freelance health writer in New York. She was awarded the 2004 and 2011 journalistic Achievement Award from the American Society for Aesthetic Plastic Surgery. Recently, she was named the 2011 National Newsmaker of the Year by the Community Anti-Drug Coalitions of America. She's also been awarded the Arthritis Foundation's Northeast Region Prize for Online Journalism, the Excellence in Women's Health Research Journalism Award, the Gold Award for Best Service Journalism from the Magazine Association of the Southeast, a Bronze Award from The American Society of Healthcare Publication Editors, and an honorable mention in the International Osteoporosis Foundation Journalism Awards. She was part of the writing team awarded a 2008 Sigma Delta Chi award for her part in a WebMD series on autism. Mann has a graduate degree from the Medill School of Journalism at Northwestern University in Evanston, Ill.
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