biostudies-literatureHu YHealth and Medical Research Funde103857https://www.ebi.ac.uk/biostudies/studies/S-EPMC12258346biostudies-literatureUnknown15(7)<h4>Background</h4>Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer mortality worldwide. Despite the organised CRC screening programme, the uptake rate of the population-based CRC screening was still low. Thus, we will conduct a randomised controlled trial in a community setting to evaluate the effectiveness of a theory-based chatbot in promoting CRC screening uptake.<h4>Methods and analysis</h4>A total of 500 eligible participants will be randomly assigned to a WhatsApp Messenger-initiated chatbot outreach group or a standard text reminder group at a ratio of 1:1. The intervention group will deliver Chinese culturally tailored education texts and videos developed based on the Health Belief Model and the Trans-Theoretical Model. The control groBMJ openTheory-based chatbot for promoting colorectal cancer screening in a community setting in Hong Kong: study protocol of a randomised controlled trial.PMC1225834620210761Tang RSYDong DHu YWong SYSLam TYTLau WMMeng MLHWang ZJMo PKHSung JJYWu XfalseTheory-based chatbot for promoting colorectal cancer screening in a community setting in Hong Kong: study protocol of a randomised controlled trial.<h4>Background</h4>Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer mortality worldwide. Despite the organised CRC screening programme, the uptake rate of the population-based CRC screening was still low. Thus, we will conduct a randomised controlled trial in a community setting to evaluate the effectiveness of a theory-based chatbot in promoting CRC screening uptake.<h4>Methods and analysis</h4>A total of 500 eligible participants will be randomly assigned to a WhatsApp Messenger-initiated chatbot outreach group or a standard text reminder group at a ratio of 1:1. The intervention group will deliver Chinese culturally tailored education texts and videos developed based on the Health Belief Model and the Trans-Theoretical Model. The control gro2025-01-01T00:00:00Z2025 Jul2026-06-15T06:11:28.14Z2026-06-15T03:08:20.982ZS-EPMC122583464063984110.1136/bmjopen-2025-103857