Background <p>Delayed bleeding is a severe complication of gastric endoscopic submucosal dissection (ESD). We conducted a study to evaluate the effectiveness and feasibility of a simple aspiration method for preventing delayed bleeding after gastric ESD.</p> Methods <p>The clinical, endoscopic and pathological data of patients who underwent ESD for early gastric cancer and other gastric lesions at our center from January 2022 to December 2024&#xa0;was retrospectively reviewed. Patients who underwent aspiration method were categorized into the aspiration group, and those without aspiration method were included in the control group. The incidences of massive delayed bleeding and overall delayed bleeding were compared between two groups.</p> Results <p>Three hundred sixty-four patients with 364 lesions were included in this study. 143 were enrolled in the aspiration group and 221 were enrolled in the control group. The baseline characteristics of the two groups are comparable. The incidence of massive delayed bleeding and overall delayed bleeding was significantly lower in the aspiration group compared to control group (0.7 vs. 5.4%, <i>P</i> = 0.018 for massive delayed bleeding; 7.0 vs. 15.4%, <i>P</i> = 0.016 for overall delayed bleeding), especially in lesions located in the middle and lower thirds of the stomach (0.9 vs. 6.8%, <i>P</i> = 0.044 for massive delayed bleeding, 7.3 vs. 16.8%, <i>P</i> = 0.024 for overall bleeding), lesions with longer procedure duration (0 vs. 9.6%, <i>P</i> = 0.020 for massive delayed bleeding, 10.3 vs. 24.6%, <i>P</i> = 0.018 for overall bleeding), and lesions performed by experienced endoscopists (1.0 vs. 7.7%, <i>P</i> = 0.040 for massive delayed bleeding, 9.2 vs. 19.0%, <i>P</i> = 0.036 for overall bleeding).</p> Conclusions <p>Our study suggested that the aspiration method was a simple, safe, and effective method for preventing delayed bleeding following gastric ESD, particularly in lesions with high-risk factors for delayed bleeding.</p>