The aim of this randomized, triple-blind, parallel-group clinical trial was to evaluate the effects of calcium hydroxide (CH), diclofenac sodium (DCS), and their combination (CH+DCS) as intracanal medicaments on post-endodontic pain in mandibular molars diagnosed with symptomatic apical periodontitis. Ninety patients were randomly assigned to three groups (CH, DCS, or CH+DCS; n=30 each). Pain intensity was recorded using a 100 mm Visual Analog Scale (VAS) over 7 days following treatment, and the number of analgesic tablets taken was also recorded. Statistical analyses were performed using Kruskal-Wallis, Friedman, Wilcoxon signed-rank, and Chi-square tests, with significance set at 0.05. The null hypothesis stated that there would be no significant difference in post-endodontic pain among the groups.