Rising life expectancy has been suggested as a determining factor behind the start of modern economic growth. On the basis of information relating to elite groups, economic historians have thus questioned the idea, prevalent among most demographers, that life expectancy remained quite stable until around 1800. There is still a scarcity of data on the long-term evolution of life expectancy able to support this claim. We present data on medical professionals in the Netherlands to study the evolution of life expectancy at age 25 in birth cohorts from the sixteenth to the early twentieth centuries. We compare the medical professions with groups without formal medical knowledge - clergymen, visual artists, notable Dutch people, and members of the nobility and patriciate - thereby providing clues about the role of medicine as a factor behind the mortality decline. We used event history models to estimate the length of life. We observe very strong increases in survival in all selected groups, starting in the cohorts born in the seventeenth century. While medical professionals were no exception to this trend, their life expectancy did not increase faster than that of other groups; for a long time, medical knowledge seems to have provided only limited advantages to those who possessed it.