Two selective cyclooxygenase type 2 (COX-2) inhibitors, celecoxib (Celebrex) and rofecoxib (Vioxx), are currently being monitored in the New Zealand Intensive Medicines Monitoring Programme (IMMP),1 which undertakes nation-wide prospective observational cohort studies on selected new medicines for a period of 4 to 5 years after the drugs are put on the market. Case details involving a severe exacerbation of psoriasis after the use of rofecoxib were forwarded to the IMMP as part of its normal monitoring process. The prescriber and the patient (a public health physician) were contacted for further information and permission to publish the case.