Summary Background Aspirin increases the risk of gastrointestinal bleeding. Aim To investigate the risk of lower gastrointestinal bleeding (LGIB) in aspirin users. Methods Low‐dose (75‐325 mg daily) aspirin users and controls matched by age, gender and enrollment time in a 1:5 ratio were selected from 1 million randomly sampled subjects in the National Health Insurance Research Database of Taiwan. Cox proportional hazard regression models were developed to evaluate the predictors of LGIB with adjustments for age, gender, comorbidities including coronary artery disease, ischaemic stroke, diabetes, hypertension, chronic kidney disease, liver cirrhosis, chronic obstructive pulmonary disease, dyslipidemia, uncomplicated peptic ulcer disease, history of peptic ulcer bleeding, and concomitant use of clopidogrel, ticlopidine, warfarin, nonsteroidal anti‐inflammatory drugs (NSAIDs), cyclooxygenase‐2 inhibitors, steroids, proton pump inhibitors (PPIs), histamine‐2 receptor antagonists (H2RAs), nitrates, alendronate, selective serotonin reuptake inhibitors (SSRIs) and calcium channel blockers. Results A total of 53 805 aspirin users and 269 025 controls were included. Aspirin group had a higher incidence of LGIB within 1 year than control group (0.20% vs 0.06%, P<.0001). Aspirin (hazard ratio HR: 2.75, 95% confidence interval CI: 2.06‐3.65), NSAIDs (HR: 8.61, 95% CI: 3.28‐22.58), steroids (HR: 10.50, 95% CI: 1.98‐55.57), SSRIs (HR: 11.71, 95% CI: 1.40‐97.94), PPIs (HR: 8.47, 95% CI: 2.26‐31.71), and H2RAs (HR: 10.83, 95% CI: 2.98‐39.33) were significantly associated with LGIB. Conclusions The risk of LGIB was higher in low‐dose aspirin users than in aspirin nonusers in this nationwide cohort. Low‐dose aspirin, NSAIDs, steroids, SSRIs, PPIs and H2RAs were independent risk factors for LGIB. Linked ContentThis article is linked to Taha and Chen et al papers. To view these articles visit https://doi.org/10.1111/apt.14114 and https://doi.org/10.1111/apt.14138.