The Bristol Stool Chart mobile app does not store any identifiable data about you, other than the date and time and quality of the stools that you record in the app. No data is sent anywhere unless you choose to share your graph and/or data with others. In this case, you will choose who receives the information.
No personal data is ever shared apart from the graph image and/or the raw data. The raw data is shared as a comma-separated (.csv) file contains two columns of data: the date and time of each stool, and the quality of each stool. Your name or details or device ID are not included in the information.