July 18, 2025 – Diarrhea can do much more than ruin your vacation. It sometimes triggers irritable bowel syndrome, a chronic condition that can linger months or even years after you’ve arrived back home.
“It’s important for people to know this can happen,” said gastroenterologist Xiao Jing Wang, MD, an assistant professor at the Mayo Clinic. “We have a lot of patients whose symptoms don’t go away, and they start doing all types of testing. It’s worth it to know that sometimes, these infections can have aftereffects that can linger.”
Nearly 1 in 8 people who get traveler’s diarrhea continue to have symptoms for at least six months, one study found. Of those, nearly 80% have symptoms for at least a year.
IBS causes belly pain and bloating, as well as diarrhea or constipation – or both. The after-travel condition is called post-infectious IBS (PI-IBS), and it can become a lifelong issue for some. “About 25% to 30% continue to have symptoms after 10 years,” said Wang.
What Is Post-Infectious IBS?
Traveler’s diarrhea, which is caused by bacterial, viral, or parasitic infections, essentially falls under the umbrella of food poisoning. You get it from picking up pathogens like campylobacteria and E. coli from poorly sanitized food or water when traveling.
Post-infectious IBS is when your symptoms persist after the infection clears.
“We now believe that a lot of IBS in this country may have started with an enteric [food poisoning] infection,” said Bradley Connor, MD, medical director of the New York Center for Travel and Tropical Medicine in New York City.
There are different theories as to how traveler’s diarrhea triggers IBS, and experts agree it’s likely a combination of things. One theory is that it triggers an autoimmune response due to a mistaken identity of a protein.
The bacteria most commonly linked to traveler’s diarrhea – shigella, campylobacter, salmonella, and E. coli – release a toxin. This toxin resembles a protein in the intestines, called vinculin, that’s important for healthy gut function.
The theory is that the immune system can confuse the two molecules. So it produces antibodies to the toxin – but also to vinculin, said Mark Pimentel, MD, executive director of the Medically Associated Science and Technology program at Cedars-Sinai Medical Center in Los Angeles. Disrupting vinculin can lead to poor gut function and an overgrowth of certain bacteria, which contributes to IBS. Pimentel published a study that found 56% of people with IBS tested positive for vinculin antibodies.
Traveler’s diarrhea can also be caused by parasites, like giardia, which has the highest rate of triggering PI-IBS. But giardia doesn’t release the toxin, meaning something else is probably at play.
It is likely a disrupted gut microbiome, said Wang. Traveler’s diarrhea changes the makeup of good bacteria and bad bacteria in the gut. “We know that there are major distortions in the microbiome when people travel,” said Connor.
The good bacteria have anti-inflammatory properties and help control how well something can pass from the gut to the bloodstream. If the gut gets overwhelmed by bad bacteria, it can lead to chronic inflammation, changes in how the intestines empty, and ultimately the symptoms of IBS.
Risk Factors for Post-Infectious IBS
It’s not known why some people develop PI-IBS, though certain things can increase your risk. It’s more common in women and young people, and some may be more likely to have it because of their genes, said Wang.
The risk tends to be higher if you have a severe case of food poisoning. Also, if you already have PI-IBS, you have a higher chance of getting it again or having more severe symptoms.
What Can You Do to Reduce Your Risk?
The most important thing is to protect yourself from getting traveler’s diarrhea. If you’re visiting high-risk regions, such as developing countries in Central and South America, Mexico, Africa, the Middle East and Asia, take these precautions:
- Avoid raw food, including unpasteurized dairy products, and raw or undercooked meat, fish, shellfish, eggs, and produce.
- Avoid salads, uncooked vegetables, and raw and unpeeled fruit.
- Avoid food and beverages from street vendors.
- Avoid tap water and ice unless it’s known to be safe, and use bottled water instead.
Taking bismuth subsalicylate (Pepto-Bismol) preventively has been shown to reduce the risk of getting traveler’s diarrhea. But the recommended dose is two tablets four times a day, which is inconvenient, said Connor.
For people with a higher risk, such as those with PI-IBS or inflammatory bowel disease, doctors may prescribe an antibiotic called rifaximin preventively if they’re travelling to high-risk regions. Rifaximin is poorly absorbed, so it doesn’t negatively affect the gut biome. It’s approved to treat traveler’s diarrhea but used preventively off-label (meaning doctors prescribe it to help prevent diarrhea, even though it’s not FDA approved for that use).
Lastly, if you get food poisoning, avoid taking antibiotics for mild traveler’s diarrhea. Antibiotics can make symptoms worse because they disrupt the microbiome even more. More severe cases caused by certain bacteria may need antibiotics. “It’s OK to use them if your doctor says you need it,” said Wang.