Background: The present study aimed to examine the effectiveness of mindfulness-based stress reduction training on negative emotions with gastrointestinal disorders. Method: A quasi-experimental study was designed with pretest-posttest using a control group. The study sample consisted of 30 male patients (referred to internal experts and admitted to Abbasi Hospital of Miandoab in 2016) with gastrointestinal disorders (Irritable Bowel Syndrome, peptic ulcer, and duodenal ulcer) based on diagnostic criteria (ROME-III) who were selected by purposive sampling method. The patients were randomly divided into two experimental and control groups. After performing the pretest using Depression, Anxiety, and Stress Scales (DASS), the experimental group received mindfulness-based stress reduction intervention during the eight sessions of one and a half hour, while the control group received no psychological intervention; and after the end of the sessions, the posttest was performed for both groups using the same tools. The collected data were analyzed through covariance analysis (ANCOV) by using SPSS-18 software. Results: The mean scores of negative emotions rates of experimental group significantly decreased after receiving the mindfulness-based stress reduction intervention (P
