Non-steroidal anti-inflammatory drugs are commonly used to reduce inflammation and pain associated with arthritis. However, non-steroidal anti-inflammatory drugs induce gastrointestinal side-effects such as dyspeptic symptoms, duodenal or gastric ulcers and, in some cases, serious complications. The aim has been to compare the benefits with the drawbacks of non-steroidal anti-inflammatory drug treatment using a hypothetical population representing patients with arthritis. A problem description was made on the basis of a literature review, and a simple and hypothetical health economic model was constructed. Including direct and indirect costs, the annual total costs in Sweden for gastrointestinal side-effects per non-steroidal anti-inflammatory drug user were estimated to be 3,420 SEK (438 US$), and the approximated costs of arthritis were 60,000 SEK (7,692 US$). The benefits of non-steroidal anti-inflammatory drug treatment were found to outweigh the drawbacks if the patient's arthritis symptoms, expressed as a difference in utility value between having and not having symptoms of arthritis, are improved by 6% or more. Costs for non-steroidal anti-inflammatory drug-induced gastrointestinal side-effects should be evaluated in relation to the benefits of non-steroidal anti-inflammatory drugs in the treatment of inflammation and pain. A simple modelling approach indicated that treatment with non-steroidal anti-inflammatory drugs may be highly cost-effective as both the clinical and economic benefits for patients responding to such treatment out-weighed possible drawbacks.