The appropriateness of further wide prevalence of diagnostics of gastroesophageal reflux disease, functional non-ulcer dyspepsia and irritable bowel syndrome is discussed. All these diseases are believed to be found in 30-50% of adults. It is very difficult to find a healthy person taking into account such an approach to the problem. As a matter of fact, gastroesophageal disease was invented by merging two different diseases: esophagitis and reflux esophagitis plus such a prevalent symptom as heartburn. All this leads to the hyperdiagnosis of this disease. The irritable bowel syndrome also includes two conditions: that of the irritable large intestine and dyskinesia of the small one. They are very different. The application of the diagnosis of functional dyspepsia leads to the practical disappearance of the diagnosis of chronic gastritis. At that symptoms of the dyskinetic form of functional dyspepsia coincide with minor symptoms of gastric carcinoma, which can lead to late diagnostics of this oncological disease. In this connection, it is necessary to narrow the limits of these diseases because their actual prevalence is much lower than that found in medical literature.