BACKGROUND: Intestinal ultrasound has been proposed as a tool to assess non-inflammatory functional gastrointestinal disorders, including constipation and faecal loading. However, well-defined sonographic criteria for these conditions are currently lacking. AIM: To identify and establish specific sonographic parameters that could be used to assess constipation and faecal loading with intestinal ultrasound. METHODS: We conducted a Research and Development/University of California Los Angeles appropriateness method exercise. A multidisciplinary, international panel comprising 14 experts in adult and paediatric gastroenterology and one radiologist experienced in gastrointestinal imaging rated the appropriateness of 57 statements using a 9-point Likert scale over two rounds of voting. Based on the median panel rating and level of disagreement, statements were categorised as appropriate, inappropriate or uncertain. RESULTS: 43 statements were deemed appropriate after two rounds of voting, while three were rated as inappropriate and five as uncertain. Intestinal ultrasound was determined to be an appropriate modality for the assessment of faecal loading. Posterior acoustic shadowing and echogenic reflections were considered important sonographic parameters for the assessment of faecal loading. A rectal diameter of 30 mm was considered appropriate to define faecal loading in paediatric patients, although no recommendation was made for adult patients due to a paucity of data. CONCLUSION: The expert panel considered intestinal ultrasound an appropriate modality for evaluating constipation and faecal loading. Further prospective research is required, especially in adult patients, to define sonographic metrics of luminal contents to broaden its application in the assessment of functional gastrointestinal disorders.