Oxycodone is a semisynthetic codeine derivative that has been used both as an analgesic and antitussive. In the mid 1990s, OxyContin was introduced as a slow-release formulation of oxycodone for use in patients with moderate to severe chronic pain from such ailments as arthritis, vertebral disc disease, and cancer. Doctors wrote 6.9 million prescriptions for OxyContin from May 2000 through May 2001. Thus, it is no surprise that hospitals and medical examiners' offices across the country have seen an increasing number of admissions and deaths resulting from oxycodone abuse and overdose. The laboratory identifies oxycodone as part of its routine abused and therapeutic drug-testing procedures. Routine gas chromatographic analysis of bile or urine in many of these cases revealed unidentified peaks in the region of oxycodone that appeared to be oxycodone metabolites. In humans, the only documented metabolites of oxycodone are oxymorphone and N-desmethyloxycodone (noroxycodone). This study attempts to characterize these compounds as "presumptive" metabolites based on circumstantial evidence from known metabolic pathways of oxycodone in other species, as well as of other opiates and narcotic analgesics.