AIMS: To determine the prevalence, characteristics, expenditure and predictors of complementary medicine (CM) use in Australian adults living with gastrointestinal disorders (GID). METHODS: A cross-sectional study involving 2,025 Australian adults was conducted. Participants were recruited through purposive convenience sampling. Descriptive statistics were conducted to report the prevalence of people living with GIDs and their CM use, including CM products, mind-body practices and CM practitioner services. Chi-square test and independent-samples t-test were used to determine the associations between sociodemographic or health-related variables with CM use. Binary logistic regression was conducted to determine the significant predictors of CM use in GID participants. Economic data was calculated based on the mean out-of-pocket expenditure on CM. RESULTS: Of the 293 participants reporting a GID, 186 (63.5%) used CM products, 55 (18.8%) used a mind-body practice and 141 (48.1%) visited at least one CM practitioner in the last 12 months. Collectively, the majority of GID participants using any type of CM were female, aged 40-49 years, married and employed. The mean score for health-related quality of life was 49.6 out of 100 in GID participants and 68.2 in participants without a GID (p < 0.001). Average annual out-of-pocket expenditure on CM products was AUD127.29 by CM products users with a GID. The predictors of CM products, mind-body practices and CM practitioner services use differed. Of the 111 CM product users with a GID, 103 (92.8%) disclosed all or some of their CM use to general practitioner, 89 (80.2%) to specialist doctor, 79 (71.2%) to pharmacist and 69 (62.1%) to hospital doctor. CONCLUSIONS: A substantial proportion of Australian adults living with GID use CM products, mind-body practices and CM practitioner services. This study provides important insights to inform and guide the development of a more coordinated health care services for individuals living with GID.