Objectives: This retrospective, observational study aimed to evaluate the tolerance and efficacy of polyethylene glycol 4000 plus electrolytes (PEG 4000) in elderly patients with chronic constipation. Methods: PEG 4000 powder was orally administered once daily at a dose of one or two 6.9 g sachets as the initial dose. The outcome measures were changes in the Cleveland Clinic Constipation Score (CCCS) and the Bristol Stool Form Scale (BSFS) value before and 2 weeks after drug administration. Results: This study included 324 patients aged >= 65 years (mean age: 78.6 +/- 7.6 years, range: 65-100 years) with chronic constipation. The total CCCS was noted to significantly improve from 11.5 +/- 4.6 at baseline to 7.4 +/- 5.2 after drug administration. All CCCS sub-scores also improved significantly. The average BSFS value at baseline (2.5 +/- 1.6) significantly improved to 4.3 +/- 1.1 after treatment. Side effects (16 events) were observed in 13 patients (4.0%), with the most common being diarrhea (6 patients, 1.9%). All events were mild in severity, with none of the symptoms being serious. The cumulative treatment continuation rate at 1 year was 83.1%. Conclusions: PEG 4000 treatment was safe, effective, and well tolerated in elderly patients with chronic constipation. Thus, it appears to be a promising drug that can be continued for a long time.