“There are some patients that we cannot help; there are none whom we cannot harm.”

Attributed to Arthur L Bloomfield

Before you next get into your car or walk out into the street, reflect that the number of deaths from road crashes in the United Kingdom is about 3400 a year.1 Elsewhere in the world the rates are up to six times higher.2 Now compare that with the extrapolated figure for the United Kingdom of more than twice that number of deaths each year from adverse drug reactions, estimated from the results of a prospective study published in this theme issue of the BMJ.3 Now try to estimate the benefit to harm balance of a road trip and the benefit to harm balance of a drug that you have recently used.

But drugs are far from being the only interventions we use in health care; even when drugs are prescribed they are often only part of an overall plan of care. Other interventions include lifestyle …