A clinical study was performed to evaluate the effectiveness of Zomepirac in 27 patients who had undergone bone surgery, 13 patients who had soft tissue surgery and 7 non-surgical patients admitted to the department of orthopedic surgery of Hanyang University Hospital from Oct., 1981 to Nov., 1981. The conclusions were as follows: 1. To decrease pain by half, Zomepirac was determined to be much more effective in patients with severe pain than in patients with moderate pain. 2. The initial pain relief was also more marked in patients with severe pain than in patients with moderate pain. 3. The duration of analgesia with Zomepirac was longer in patients with severe pain than in patients with moderate pain. 4. The duration of pain relief after medication with Zomepirac was from 1 to 3 hours in 79.3% of patients. 5. The results of treatment were excellent in 5 patients (10.6%), very good in 5 patients (10.6%), good in 7 patients (14.9%), fair in 4 patients (8.5%), poor in 1 patient (2.2%), when the intensity of pain before treatment was severe; but fair in 13 patients (27.7%), poor in 11 patients (23.3%), when the pain was moderate. Thus the clinical results demonstrated that this medication was remarkably effective in patients with severe pain and much less so in patients with only inoderate pain. 6. Side effects were mild transient drowsiness in 3 patients (6.3%) and gastric colic in 2 patients (4.3%). In patients with drowsiness was continuously administered. The gastric colic subsided when the medication was combined with antacid.