1. Two separate placebo-controlled studies of parallel design were carried out to evaluate the efficacy of single doses (400 mg) of soluble ibuprofen, ibuprofen liquid in a gelatin capsule and ibuprofen tablets (Nurofen), in patients with postoperative pain after third molar surgery. 2. All ibuprofen preparations provided significant pain relief (P less than 0.05) over a 6 h investigation period. 3. Mean pain scores after ibuprofen tablets and ibuprofen liquid in a gelatin capsule were similar. 4. Soluble ibuprofen 400 mg provided an earlier onset of pain relief (20 min) than ibuprofen tablets (30 min). 5. No unwanted effects were reported in the various ibuprofen treatment groups. 6. The ibuprofen preparations evaluated in this study are effective up to 4 h for controlling postoperative pain after third molar surgery. The soluble form is more efficacious with regard to onset of action.