Irritable bowel syndrome(IBS) and functional constipation(FC) are the most common functional gastrointestinal disorders. According to the Rome ⅢCriteria these two disorders should be theoretically separated mainly by the presence of abdominal pain or discomfort relieved by defecation(typical of IBS) and they should be mutually exclusive. However,many gastroenterologists have serious doubts as regards a clear separation. Both IBS-C and FC,often associated with many other functional digestive and non digestive disorders,are responsible for a low quality of life. The impact of the media on patients’ perception of these topics is sometimes disruptive,often suggesting a distorted view of pathophysiology,diagnosis and therapy. These messages frequently overlap with previous subjective opinions and are further processed on the basis of the different culture and the previous experience of the constipated patients,often producing odd,useless or even dangerous behaviors. The aim of this review was to analyze the most common patients’ beliefs about IBS-C and CC,helping physicians to understand where they should focus their attention when communicating with patients,detecting false opinions and misconceptions and correcting them on the basis of scientific evidence. Irritable bowel syndrome (IBS) and functional constipation (FC) are the most common functional gastrointestinal disorders. According to the Rome III Criteria these two disorders should be theoretically separated mainly by the presence of abdominal pain or discomfort relieved by defecation (typical of IBS) and However, many gastroenterologists have serious doubts as regards a clear separation. Both IBS-C and FC, often associated with many other functional digestive and non digestive disorders, are responsible for a low quality of life. The impact of the media on patients’ perception of these topics is sometimes disruptive, often suggesting a distorted view of pathophysiology, diagnosis and therapy. These messages frequently overlap with previous subjective opinions and are further processed on the basis of the different culture and the previous experience of the constipated patients, often producing odd, useless or even dangerous behaviors. The aim of this review was to analyze the most common patients’ beliefs about IBS-C and CC, helping physicians to understand where they should focus their attention when communicating with patients, detecting false opinions and misconceptions and correcting them on the basis of scientific evidence.