The efficacy of a non-steroidal anti-inflammatory agent, ibuprofen, was evaluated in pain control following periodontal surgery. This type of agent acts peripherally by inhibiting the release of prostaglandins and minimizing the local inflammatory response. Thus there may be an advantage in pre-treatment administration of the drug so as to delay or even prevent postoperative pain. The study was multicentre, involving a Public Hospital Periodontal Unit, two specialist periodontal practices in Sydney, NSW, and two in Canberra, ACT. One hundred and twenty-seven patients who were to undergo periodontal surgery were randomly given either two 200 mg tablets of ibuprofen or two matching placebo tablets at least 30 minutes before administration of local anaesthesia. The procedure was double blind: neither the patient nor the clinician was aware of the tablet identity. Postoperatively, all patients were given labelled ibuprofen for pain relief, but were randomly divided into two groups: As directed who were instructed to take the drug regularly for two days postoperatively, and As required, who were to take the drug only if needed for pain relief. All patients completed a diary recording quantity and time of medication, and regular assessment of pain experience utilizing a visual analogue scale. The As directed group showed no significant difference in pain experience between pre-operative and post-operative only medication, but the As required group experienced significantly less pain and requirement for medication if the ibuprofen was administered pre-operatively.