A double blind randomized analgesic trial was carried out in patients suffering from pain after removal of an impacted lower wisdom tooth. In a repeated dose regimen, 120 patients received one of three different analgesics: phenazone, phenazone plus dextropropoxyphene, or paracetamol. The assessments of pain were made hourly on a visual analogue scale and the evaluation was carried out according to a method which considers repeated dose intake. The analgesic efficacy of 500 mg phenazone was similar to 500 mg of paracetamol. The pain reduction seemed adequate in most patients and no statistical differences were obtained between the treatment drugs. All analgesics were taken when needed, and the time interval from end of operation to first tablet intake, as well as the pain score at first tablet intake, were factors which significantly influenced the efficacy of the drugs. Therefore, these factors may be of significant importance in the evaluation of analgesics in small sample studies.