A month of vomiting led to a stomach mass—and a 1.5-litre prescription

The symptoms looked familiar

A 63-year-old woman presented after about a month of nausea, vomiting, reduced appetite and burning upper-abdominal pain that extended around her right side towards her back. She had type 2 diabetes and obesity and had taken semaglutide for roughly a year. Her weight had fallen by about 18 kg, with faster loss during the month in which the vomiting developed.

That combination creates an easy cognitive shortcut. GLP-1 receptor agonists commonly cause nausea, vomiting and reduced appetite, particularly around initiation or dose escalation. They also slow gastric emptying: food remains in the stomach longer. Yet persistent vomiting, pain and unexpectedly accelerating weight loss cannot safely be filed as ordinary treatment effects without reconsidering the differential.

The first images did not settle it

CT of the abdomen and pelvis showed mildly dilated bile ducts and a mildly distended stomach containing semisolid material. Those findings opened several possibilities rather than providing one answer. Pancreatic or biliary disease, gastric-outlet obstruction, medication-related delayed emptying and retained food all remained relevant. Further biliary imaging did not explain the full symptom pattern.

The decisive test was upper gastrointestinal endoscopy. A camera passed into the stomach showed a large gastric bezoar: a compact mass of material that had not moved onward or been digested. This was not simply the normal meal residue that a scan might catch. The endoscopic appearance supplied a physical explanation for the prolonged nausea, vomiting and poor intake.

Did semaglutide cause it?

The association is plausible. Semaglutide delays gastric emptying, and impaired gastric motility is a recognised risk factor for bezoar formation. The MHRA also warns that people taking GLP-1 medicines may retain gastric contents despite fasting, which matters during anaesthesia and deep sedation. In this patient, the drug exposure, symptoms and retained food formed a coherent sequence.

A single case cannot prove causation. Bezoars also occur with previous gastric surgery, autonomic neuropathy, particular foods and other causes of poor motility. The report cannot show whether the mass would have formed without semaglutide, estimate the risk among users or identify which patient is susceptible. “Semaglutide-associated” is therefore more defensible than “semaglutide-caused”.

The 1.5-litre reveal

The medication was withheld in hospital and the confirmed bezoar was treated with diet cola. The patient drank 1.5 litres under clinical supervision. By the second day, she described a pulling sensation followed by relief of the nausea and abdominal discomfort. Repeat endoscopy no longer showed the gastric mass. She resumed a normal diet and left hospital without the original symptoms.

Cola dissolution sounds like an improvised trick, but it has a published history. Its acidity, carbon dioxide bubbles and other constituents may soften or break down plant-fibre bezoars, although the active mechanism is uncertain. A 2013 systematic review identified 24 reports containing 46 patients. Cola alone completely dissolved the phytobezoar in half; cola plus additional endoscopic treatment was successful in 91.3%.

Those percentages should not be mistaken for trial-quality efficacy. The review pooled case reports and small series from 2002 to 2012, used varied administration methods and contained different bezoar types. Publication bias is likely. Some bezoars are harder to dissolve, and partial fragmentation can migrate and cause obstruction. Diagnosis, clinical stability, composition and local endoscopy expertise all change management.

Why this is not a home remedy

The memorable treatment creates the package’s main safety risk. A person with vomiting and abdominal pain cannot know that a bezoar is present, what it contains or whether obstruction, perforation, pancreatitis, gallbladder disease or another urgent condition is responsible. Drinking a large volume of cola could delay assessment, worsen symptoms or be inappropriate because of diabetes, fluid restrictions or aspiration risk.

In the published case, clinicians had examined the patient, performed imaging, confirmed the mass by endoscopy, judged her stable, stopped the suspected medicine and planned reassessment. The disappearance was then checked with another endoscopy. Removing those steps turns supervised case management into unsafe self-treatment.

The UK takeaway

Current UK safety advice remains broader than this rare case. The MHRA advises clinicians to ask specifically about privately supplied GLP-1 medicines because they may not appear in the medical record. Severe, persistent abdominal pain—especially pain radiating to the back with nausea or vomiting—requires urgent assessment for pancreatitis and other causes. Suspected adverse reactions can be reported through Yellow Card.

Patients should not stop prescribed semaglutide abruptly or alter the dose without speaking to the treating clinician. For doctors, the useful question is whether the duration, severity or trajectory still fits an expected adverse effect. A month of vomiting, pain and accelerating weight loss deserved a fresh problem representation. Endoscopy, rather than the unusual bottle at the end, solved the mystery.

Source note

The case appeared in the New England Journal of Medicine on 25 September 2025 and was recirculated by several independent outlets in July 2026. PubMed and the journal record showed no linked correction, expression of concern or retraction when checked on 21 August 2026. No patient image, quotation or unnecessary identifying detail is reproduced.