At least two factors relating to pain management using oral analgesics suggest that combination strategies merit consideration: many pains arise from more than one physiological cause and current analgesics have adverse effect profiles that might be reduced by combination with another agent in smaller doses or with less frequent dosing. In addition to increased convenience, combinations sometimes also result in the unexpected benefit of synergy. But not all pains, clinical settings or combinations merit the extra expense or other potential negative features of fixed-ratio products. This review examines the multiple basic science, clinical and pharmacoeconomic issues relating to analgesic combinations and the methodologies available for assessing these issues.