Indigestion is common, but reported rates vary according to the definition, survey method, country, and time period. U.S. estimates indicate that indigestion affects up to 20% of people each year. In clinical settings, about 7 in 10 U.S. patients who see a doctor for indigestion are diagnosed with functional dyspepsia, a disorder defined by recurring upper-digestive symptoms without a structural explanation identified by the diagnostic framework used.
Contents
- How common is indigestion?
- Functional dyspepsia in the United States, Canada, and the UK
- Which functional dyspepsia patterns are reported?
- Age, symptoms, and quality of life
- Health-care use and medicines
- Global functional dyspepsia statistics
How common is indigestion?
The National Institute of Diabetes and Digestive and Kidney Diseases says indigestion affects up to 20% of people in the United States each year. This is an annual U.S. estimate, so it should not be read as the percentage of people experiencing symptoms on one particular day or as a worldwide rate. The same NIDDK source reports that about 7 in 10 U.S. patients who see a doctor for indigestion receive a diagnosis of functional dyspepsia.
These two figures describe different groups. The estimate of up to 20% concerns people in the United States each year, while the 7-in-10 figure concerns U.S. patients who seek medical care for indigestion. They therefore should not be combined into a single risk calculation. The NIDDK indigestion facts page was last reviewed in March 2025.
The term indigestion is used broadly in everyday language. The studies below use the more specific Rome IV category of functional dyspepsia, abbreviated FD. Because the definitions and sampling methods differ, the results are best compared within each study rather than treated as interchangeable measurements.
Functional dyspepsia in the United States, Canada, and the UK
A 2018 survey published in The Lancet Gastroenterology & Hepatology collected 6,300 adult responses across the United States, Canada, and the UK. After 369 inconsistent responses were excluded, 5,931 usable responses remained. The final country samples were 1,949 adults in the U.S., 1,988 in Canada, and 1,994 in the UK.
Using Rome IV criteria, FD prevalence was 12% in the U.S., 8% in Canada, and 8% in the UK. Across the combined three-country sample, 9% fulfilled Rome IV FD criteria. These are survey estimates from the 2018 study, not a single current estimate for every country or for all forms of indigestion.
| Location or sample | Rome IV functional dyspepsia prevalence | Survey detail |
|---|---|---|
| United States | 12% | 1,949 adults |
| Canada | 8% | 1,988 adults |
| United Kingdom | 8% | 1,994 adults |
| Combined sample | 9% | 5,931 usable responses |
The country-level figures show why geography matters in indigestion statistics. The U.S. estimate in this survey was higher than the estimates for Canada and the UK, while the combined result was lower than the U.S. figure because it includes all three samples. None of these percentages establishes that one country causes more indigestion; they describe results from this particular survey and diagnostic definition.
Which functional dyspepsia patterns are reported?
The 2018 survey divided Rome IV FD cases into postprandial distress syndrome, epigastric pain syndrome, and an overlapping group. Among all Rome IV FD cases, 61% were classified as postprandial distress syndrome (PDS), 18% as epigastric pain syndrome (EPS), and 21% as overlapping PDS and EPS.
The country-specific prevalence figures were lower than the percentages describing the composition of FD cases because they use different denominators. In the U.S. subgroup, PDS prevalence was 7%, representing 137 cases; EPS prevalence was 2%, representing 36 cases; and overlapping FD prevalence was 3%, representing 59 cases. In Canada, PDS prevalence was 5% (106 cases), EPS prevalence was 2% (35 cases), and overlapping FD prevalence was 1% (26 cases). In the UK, PDS prevalence was 5% (96 cases), EPS prevalence was 1% (26 cases), and overlapping FD prevalence was 2% (30 cases).
| Rome IV pattern | United States | Canada | UK |
|---|---|---|---|
| Postprandial distress syndrome | 7% (137 cases) | 5% (106 cases) | 5% (96 cases) |
| Epigastric pain syndrome | 2% (36 cases) | 2% (35 cases) | 1% (26 cases) |
| Overlapping FD | 3% (59 cases) | 1% (26 cases) | 2% (30 cases) |
The overall case breakdown and the country-specific prevalence figures answer different questions. The 61%, 18%, and 21% figures describe the distribution within FD cases in the combined study population. The country percentages describe how common each pattern was in each national subgroup.
Age, symptoms, and quality of life
In the 2018 survey, FD prevalence among adults aged 18–34 years was 12%, or 200 of 1,693 people in that age group. This age-specific result is from the three-country survey and should be kept separate from the country estimates and from the broader global studies.
The same survey measured somatic symptoms and health status. People with FD had a mean of 3.5 somatic symptoms, compared with 6.2 in controls. On the SF-8 physical component score, the FD group had a mean score of 41.8, compared with 49.9 among controls. On the SF-8 mental component score, the corresponding means were 40.4 for people with FD and 49.9 for controls.
These comparisons show differences between the FD group and the control group in the measures reported by the study. They do not by themselves identify why the groups differed, and the mean values should not be interpreted as an individual prediction. The survey’s control comparisons are useful for describing the burden measured in that sample without treating every indigestion symptom as functional dyspepsia.
Health-care use and medicines
Health-care contact was more common among people with FD than among controls in the 2018 survey. Forty-four percent of people with FD had seen a doctor for gastrointestinal health problems, compared with 21% of controls. In the overlapping subgroup, 73% reported health-care visits more than once a year, compared with 56% of controls.
Medication-use figures also varied by group. Fifteen percent of people with FD used antiemetics at least once a week, compared with 2% of controls. Among the overlapping subgroup, 36% used acid-suppressing drugs at least once a week. These statistics describe reported use in the 2018 survey; they do not establish that a medicine caused, prevented, or resolved functional dyspepsia.
The health-care results should also be read alongside the NIDDK estimate that about 7 in 10 U.S. patients who see a doctor for indigestion are diagnosed with functional dyspepsia. The NIDDK figure concerns U.S. clinical patients, while the Lancet survey reports comparisons among defined survey groups from the U.S., Canada, and the UK. Different populations and methods mean the figures provide context rather than a direct trend line.
Global functional dyspepsia statistics
The 2025 Rome IV global epidemiology study used 54,127 internet-sample respondents from 26 countries for its FD analysis. In that study, female sex had an adjusted odds ratio of 1.36 for FD. Compared with adults aged 65 years and older, ages 18–39 had an adjusted odds ratio of 1.98, while ages 40–64 had an adjusted odds ratio of 1.49. These are adjusted associations reported by the study, not percentages of people with indigestion.
The same 2025 study reported strong associations between FD and several other Rome IV conditions. FD was associated with an adjusted odds ratio of 10.6 for comorbid irritable bowel syndrome, 10.4 for comorbid functional heartburn, and 8.74 for chronic nausea and vomiting syndrome. The figures describe comorbidity associations in the global FD analysis; they do not mean that every person with one of these conditions has FD.
A broader Rome Foundation global study covered 73,076 respondents across 33 countries, including 36,148 women and 36,928 men. In its internet survey, any Rome IV functional gastrointestinal disorder prevalence was 40.3% overall, 46.5% among women, and 34.2% among men. Within that same internet survey, Rome IV FD prevalence was 7.2% overall, 8.7% among women, and 5.8% among men. Rome IV PDS prevalence was 6.1% overall, 7.5% among women, and 4.8% among men.
The broader study also reported a Rome IV FD prevalence of 4.8% overall in its household survey. In internet surveys, FD prevalence ranged from 2.2% in Japan to 12.3% in Egypt. In household surveys, the reported range was from 0.7% in India to 19.4% in Bangladesh. These country figures are estimates from the study’s stated survey types and should not be treated as forecasts or as evidence that the two survey methods measure the same population in the same way.
Taken together, the available statistics show why indigestion prevalence depends on the question being asked: annual U.S. indigestion estimates, doctor-seeking populations, Rome IV diagnostic criteria, internet samples, and household surveys produce distinct measurements. Keeping the source, geography, measurement period, denominator, and survey method visible is essential when interpreting the numbers.