Mefenamic acid is a potent analgesic possessing both anti-inflammatory and antipyretic properties. It is completely absorbed one to two hours after intake. Majority of patients however, expect relief of pain within 15 minutes. A new oral mefenamic acid containing sodium lauryl sulfate with a dissolution rate of 98 per cent in 15 minutes has been introduced. This phase 4 clinical trial was conducted to evaluate the onset of pain relief upon administration of mefenamic acid 500 mg combined with sodium lauryl sulfate. The study was an open, noncomparative clinical trial. Physicians all over the Philippines were asked to fill up a standard 3-page case report form. A total of 2,617 patients with a mean age of 36 years were enrolled. Forty two per cent were males and fifty eight per cent were females. Seventy per cent of patients took the drug every 6-8 hours. Majority (78.38%) reported complete resolution of pain (54.3%) of which occurred within 15 minutes, increasing to 84.93% within 30 minutes). Only 1.12 per cent showed no response. Forty one patients (1.57%) reported minor adverse reactions, majority of whose conditions improved with withdrawal of the drug. The overall assessment of clinical response was very good to excellent in 77.66 percent of patients.(Author)