If all disease was caused by the four humours; if our only treatments were blood-letting, purging or cold baths; and if all research was forbidden, medicine would be much easier. But medicine has changed, and is changing, more than most practitioners recognise. While no organisation keeps a precise count of the number of diseases, the expert system DiagnosisPro (http://www.diagnosispro.com) claims to assist with the diagnosis of over 11 000 diseases. Thus, diligent generalists such as general practitioners and physicians who updated their learning on one disease every day would take over 30 years to examine current knowledge just once. But medical knowledge is not static: MEDLINE now adds over 12 000 articles to its database per week, including more than 300 reports of randomised trials. For generalists, and those who help with continuing medical education of generalists, there is a clear need to make good use of what we know and to develop parsimonious strategies to cope with the growth of medical knowledge, with a clear focus on what will improve patient care.