OBJECTIVES:  Clinical trials for gastrointestinal (GI) tract diseases often involve patient-reported outcome (PRO) item, specifically stool frequency, as a primary outcome measure. The aim of this study was to examine patients’ understanding of how to accurately report stool count. METHODS:  451 participants, including 87 participants diagnosed with at least one of GI related disease (e.g., Gastroesophageal Reflux Disease, Irritable Bowel Syndrome, Ulcerative Colitis, and Crohn’s disease), completed an online survey. Participants were asked “If you were participating in a clinical trial that asked you to record the number of stools you had each day and you had a stool and returned to the bathroom 5 minutes later and had a second stool, would you record this as 1 stool or 2 stools?” in a multiple choice format. Demographic information, including age, education level, and household income were also recorded. RESULTS:  66.3% of participants with GI related diseases provided the correct answer, 2 stools. 33.7% of participants chose the incorrect answer, where 18.2% indicated that they did not have enough information to answer the question, 9.4% stated that it depended on the amount of stool at each occurrence, and 6.1% chose 1 stool. Participants without GI related disease scored similarly with 66.4% answering correctly. The two groups did not differ in age, education, or household income. CONCLUSIONS:  Though the majority of the participants answered the question correctly regardless of whether they were diagnosed with a GI related disease, results suggest that a third of participants were not able to determine and accurately record the stool frequency in the given scenario. These findings are consistent with regulatory guidance from the FDA (2012) on providing patients with standardized instructions and training on completing diaries for recording stool frequency.