Indigestion tablets may trigger food allergies, according to a study by scientists in Austria.
One in 10 people regularly take indigestion pills
They carried out tests on around 300 people and found that those who took anti-acid pills were more likely to suffer an allergic reaction.
Speaking at the World Allergy Organisation congress, they said the pills may interfere with digestion.
This may cause food to enter the intestines before it is fully broken down, triggering an attack.
Professor Erika Jensen-Jarolim and colleagues at the University of Vienna gave half of the people in their study a drug call ranitidine, which acts in the same way as indigestion tablets. The remaining volunteers were given a dummy or placebo pill.
None of these people had reported any food allergies in the past.
They found that people taking the drug developed or showed signs of food allergy symptoms. None of those in the placebo group showed any such signs. Tests on mice have shown similar results.
The scientists said indigestion pills may reduce levels of gastric acid in the stomach. This acid helps the stomach to break down food before it enters the intestines.
They believe low levels of this acid may result in food entering the intestines before it is broken down.
They believe the body's immune system then tries to attack the food, triggering an allergic reaction.
The scientists said eating new types of food seemed to be particularly risky. This is because the body builds up a tolerance to food that is commonly consumed. However, problems may occur when people eat foods that they haven't had before.
"Stick to the diet you know and don't try exotic foods and don't make experiments," said Professor Jensen-Jarolim.
Allergies to food can range from mild rashes to potentially life-threatening anaphylactic shocks.
"These findings are significant for those people at risk for a food allergy," said Professor Jensen-Jarolim, "since 10% of the adult population today is on antacids."
GlaxoSmithKline, which manufactures many leading indigestion remedies, said it would examine the findings.
However, a spokeswoman said the company did not believe there were any risks associated with taking its products.
"Our products have been through very extensive clinical trials and have been approved by all the government regulatory bodies," she told BBC News Online.
"We are always alert to new research that comes into the market place and if that poses any potential threat to consumers, then we will look very closely at the research and act very quickly if we think we need to.
"However, many of our products have been in on the market for 20 odd years and this isn't something we have ever come across. We are very surprised by these findings."