So far, proton pump inhibitors (PPIs) like Nexium and Prilosec have been connected to a host of harmful side effects, ranging from kidney disease and arterial injuries to the development of dementia. However, that doesn’t appear to be the end of it. A recent study indicates that the use of PPIs can cause buildup of abdominal fluid – a condition known as ascites.

Ascites is normally a symptom of other diseases, primarily cirrhosis of the liver. The fluid that accumulates in the peritoneal cavity (located beneath the diaphragm) is serious, meaning that it is a pale, clear yellow color. In addition to liver disease, it can also be indicative of cancer, heart failure and kidney disease.

The study was carried out at Aarhus University Hospital in Denmark. Published in the August edition of the journal Hepatology, the study’s original purpose was to determine the effectiveness of an ascites treatment.  What the researchers discovered was that PPI use was a probable cause of fluid accumulation in the abdomen as well as a condition known as hepatic encephalopathy, or HE. This latter condition is essentially a decrease in brain function resulting from the liver’s impaired ability to filter toxins from the bloodstream.

According to Dr. Gitte Dam, who led the study, the results indicate that the use of PPIs increases the risk of developing spontaneous bacterial peritonitis, or SBP. This is a bacterial infection found in people suffering from portal hypertension (high blood pressure in the portal vein feeding into the liver) due to cirrhosis. SBP also increases the risk of HE. Dr. Dam wrote that the team’s findings “provide support for the hypothesis that PPIs contribute to the development of HE by promoting translocation of gut bacteria.”

How does this happen? Keep in mind that the purpose of PPI medications is to literally “inhibit” the production of stomach acid. By decreasing the acidity of the stomach, a high pH (alkaline) environment is created in which gut bacteria thrive. Eventually, the bacteria reproduce at such a high rate that they run out of room and begin to pass into the circulatory and lymphatic systems. This is what increases the risk of SBP and HE.

The Danish study lends support to an earlier study that was published in April of 2015, in which researchers discovered a link between chronic bacterial infections and the use of PPI medications.

Antacids such as Prilosec (omeprazole) and Nexium (esomeprazole) are among the most frequently prescribed medications in the U.S. Available in prescription strength as well as over-the-counter forms, these medications generate approximately $14 billion every year for manufacturers like Procter and Gamble and AstraZaneca. Some medical experts believe they are over-prescribed. The condition they are used to treat – Gastroesophageal Reflux Disease, or GERD – can often be treated with simple changes in diet and lifestyle.

But with $14 billion in corporate revenue at stake, it’s small wonder that the manufacturers wouldn’t be forthcoming about the serious side effects.