Objective: Bile acid diarrhea (BAD) is an underrecognized and socially debilitating disease caused by high concentrations of bile acids in the colon. Bile acids directly and indirectly promote carcinogenesis. Here, we investigated if individuals with BAD have an increased risk of gastrointestinal (GI) cancers. Design: By using the Danish health registries, adult individuals with BAD were identified by international classification of disease 10^th revision (ICD10) code K90.8 or referral to the diagnostic ⁷⁵selenium-homotaurocholic acid test followed by prescription of a bile acid sequestrant within 365 days (n=5,245). Age and sex-matched individuals without BAD were included for comparison (n=52,450). We analyzed the cumulative incidence of GI cancers after BAD diagnosis and the odds ratios (ORs) of GI cancer eight and 15 years before BAD diagnosis/matching. Results: Cumulative incidence of GI cancer six years after BAD diagnosis/matching was 1.6% in the BAD group and 1.1% in controls (p=0.01). The ORs of total GI cancer eight and 15 years before BAD diagnosis were 6.16 (5.08–7.48) and 5.19 (4.28–6.29), respectively. Furthermore, 47 individuals with BAD (0.9%) and 250 (0.5%) controls died of GI cancer. Conclusion: This nationwide cohort study indicates an association between BAD and GI cancers. We found both a higher incidence of GI cancer after BAD diagnosis compared with controls and increased OR of GI cancer before BAD diagnosis. Bearing in mind the underdiagnosis of BAD, the delay of BAD diagnosis, and the carcinogenic effect of bile acids, these findings warrant further investigations of the risk of GI cancer in individuals with BAD.