Plain sparkling water does appear to help with digestion, particularly for people dealing with indigestion or constipation. The carbonation stimulates nerves involved in digestion and improves gallbladder function, which can make the whole process more efficient. But the picture isn’t entirely simple: for some people, especially those with acid reflux or irritable bowel syndrome, carbonated water can make things worse.
What Carbonation Does in Your Stomach
When you drink sparkling water, the dissolved carbon dioxide creates gentle pressure and stimulates the nerves that control digestive movement. This can encourage your stomach and intestines to contract more actively, helping food move through your system. CO2 also promotes mixing of stomach contents, which can improve how thoroughly food gets broken down before moving into your small intestine.
One specific effect that researchers have measured is improved gallbladder emptying. Your gallbladder releases bile to help digest fats, and carbonated water increases its contraction rate. In one controlled trial, gallbladder emptying improved from about 40% to nearly 54% after participants drank carbonated water for 15 days. Better bile flow means more efficient fat digestion and less of that heavy, sluggish feeling after meals.
Relief for Indigestion and Constipation
The strongest evidence for sparkling water’s digestive benefits comes from a double-blind trial published in the European Journal of Gastroenterology & Hepatology. Researchers split 21 people with chronic indigestion and constipation into two groups: one drank carbonated water, the other tap water, for about two weeks. The results were clear. Indigestion scores dropped significantly in the carbonated water group (from 7.9 to 5.4 on a standardized scale), while the tap water group saw no change at all. Constipation scores followed the same pattern, falling from 16.0 to 12.1 with carbonated water and barely budging with tap water.
The carbonated water group also reported feeling less full after eating. Before the study, they felt satisfied after consuming roughly 447 calories. Afterward, that threshold rose to about 590 calories, meaning their early satiety (that uncomfortable “full too fast” sensation common with indigestion) had improved. They could eat a normal-sized meal without discomfort.
The Hunger Hormone Complication
There’s one counterintuitive finding worth knowing about. Carbonated water appears to increase levels of ghrelin, the hormone your body produces when your stomach is empty to signal hunger. In a study that tested both rodents and humans, men who drank carbonated water had triple the blood levels of ghrelin compared to those who drank flat water or sparkling water that had been degassed. This was true whether the sparkling water was plain or artificially sweetened.
This doesn’t mean sparkling water will make you overeat, but it’s worth being aware of if you’re using carbonated water to curb appetite between meals. The fizzy sensation may feel filling in the moment, yet the hormonal response could leave you hungrier shortly after.
When Sparkling Water Can Backfire
If you’re prone to acid reflux, carbonated water may not be your friend. A randomized crossover trial found that carbonated beverages increased feelings of fullness, heartburn, and belching compared to flat alternatives. The carbonation didn’t appear to push stomach acid all the way up into the throat in measurable amounts, but it did provoke the uncomfortable symptoms people associate with reflux. Belching was significantly higher in the first five minutes and again between 15 and 30 minutes after drinking.
For people with irritable bowel syndrome, the picture is less studied but worth noting. Monash University, the leading research group behind the low-FODMAP diet used to manage IBS, points out that carbonated drinks can distend the stomach and intestines, potentially triggering bloating and discomfort. At least one clinical guideline for IBS recommends reducing fizzy drink intake. The evidence is mostly anecdotal at this point, but if you already struggle with gas and bloating, adding more CO2 to your gut may not help.
Sparkling Water vs. Still Water for Hydration
One common concern is whether the carbonation somehow reduces how well your body absorbs the water. It doesn’t. Research consistently shows that sparkling and still water hydrate the body equally, with no significant difference in fluid retention or urine output. So if you prefer the texture of sparkling water and it helps you drink more throughout the day, you’re not sacrificing hydration.
What About Your Teeth?
Sparkling water is slightly more acidic than still water because dissolved CO2 forms a weak acid. But according to the American Dental Association, research on extracted teeth showed that plain sparkling water and regular water had about the same effect on enamel. The risk changes if you’re drinking citrus-flavored sparkling water, which tends to have higher acid levels that can erode enamel over time. Plain or unflavored varieties are not a concern.
Who Benefits Most
Sparkling water is most helpful for people who experience sluggish digestion, feelings of uncomfortable fullness after small meals, or occasional constipation. Drinking it with or after meals may improve how efficiently your stomach processes food and how well bile flows from your gallbladder. For general digestive comfort, a glass or two a day is a reasonable amount based on the existing research, which typically used moderate daily consumption over a two-week period.
If you have reflux, frequent heartburn, or IBS with bloating as a primary symptom, still water is the safer choice. The same goes if you notice that carbonated drinks consistently leave you gassy or uncomfortable. Digestion is personal, and the best test is paying attention to how your own body responds.