Vaping can cause stomach pain through three main mechanisms: nicotine effects on gut motility and stomach acid, irritation from swallowed vapour, and inflammatory effects on the gut lining. A 2021 study published in the journal iScience found that vaping (including 0mg nicotine-free vapes) compromises the gut barrier and triggers systemic inflammation, suggesting that vape-related GI symptoms are not purely about nicotine. The American Gastroenterological Association has noted increased reports of vape-related GI symptoms over recent years.

Nicotine is a gastrointestinal stimulant, similar to how caffeine acts on the gut. It accelerates bowel motility, increases stomach acid production and relaxes the lower oesophageal sphincter (the valve between stomach and oesophagus). The combination can cause cramping, urgency to use the toilet, acid reflux, heartburn and a burning sensation in the stomach. For people prone to IBS, GORD or ulcers, nicotine in vape can noticeably worsen symptoms. Higher nicotine strengths (20mg/ml) are more likely to cause GI symptoms than lower strengths.

Swallowed vapour is the third mechanism and is often underrecognised. When inhaling, a portion of vape aerosol is swallowed rather than reaching the lungs. This means PG, VG, nicotine and flavouring compounds end up in the stomach where they can directly irritate the gastric lining. Chain vaping (rapid frequent puffs) increases the amount of swallowed vapour and worsens this effect. EVALI (e-cigarette or vaping use-associated lung injury) cases frequently include GI symptoms (nausea, vomiting, diarrhoea, stomach pain) alongside respiratory symptoms, though EVALI in the UK is rare and almost always linked to illicit THC vape products.

The 2021 iScience gut barrier study in detail

The 2021 study published in iScience exposed gut cells to e-cigarette vapour (with and without nicotine) over chronic timeframes. The researchers found that vape exposure compromised tight junctions in the gut lining, allowing increased permeability (“leaky gut”). This was associated with increased systemic inflammation, even in the nicotine-free condition, suggesting PG and VG themselves contribute to gut barrier disruption. The implications: vape-related GI symptoms may not require nicotine to develop, and chronic vaping may have effects on gut health that go beyond the symptoms most users notice. The findings are preliminary and based on cell culture rather than full clinical trials, but they align with patient-reported GI symptoms in vapers.

Why nicotine specifically causes acid reflux and heartburn

Nicotine relaxes the lower oesophageal sphincter, the muscular valve between the stomach and the oesophagus. When this valve relaxes, stomach acid can flow back up into the oesophagus, causing heartburn. Nicotine also stimulates stomach acid production directly. The combination of more acid plus a weaker valve is a textbook recipe for acid reflux. For people who already have gastroesophageal reflux disease (GORD), vaping nicotine can significantly worsen symptoms. Some vapers notice burning chest pain, sour taste in the mouth, and worsening of reflux particularly at night.

When stomach pain from vaping needs medical attention

Most occasional or mild vape-related GI symptoms resolve within hours by reducing vape use, drinking water and eating a small meal. Persistent stomach pain (more than 1-2 weeks), severe acute pain, vomiting that does not settle, blood in stool, weight loss, or severe heartburn all need GP assessment. The NHS treats GI symptoms as a routine GP matter and can refer to gastroenterology if needed. Be honest about vape use; it helps the GP form a complete picture. For severe or sudden symptoms (chest pain, severe abdominal pain, vomiting blood) call 999 or attend A&E immediately.

For UK vapers experiencing stomach pain or GI symptoms they suspect are linked to their vape, the four changes below typically resolve the problem within days to a week.

If GI symptoms persist for more than 1-2 weeks despite these changes, see your GP. The NHS treats GI symptoms as a routine GP matter and can refer to gastroenterology if needed. Common UK GP investigations include stool tests, blood tests for inflammation markers and (occasionally) endoscopy. Be honest with your GP about vape use; it helps them form a complete picture and rule in or out vape-related causes versus other GI conditions like IBS, GORD, gastritis or food intolerance.