Anecdotes can be harmful to your health !

I see lots of patients who demand/ request that I treat them with unproven treatments, such as Intravenous immunoglobulins for treating high NK cells. When I ask them why they think this will help, the commonest answer is - I read about a woman who had failed 4 IVF cycles and who then got pregnant after taking IV Ig !

The trouble is that one swallow does not make a summer - and anecdotal successes cannot be relied upon because medicine is such a complex science. Often, these women get pregnant inspite of the treatment, not because of it ! This is why controlled clinical trials are so important !

However, it's not just patients who get swayed by these success stories - we doctors also get unduly influenced by them. We are human, and we remember our successes ( who come back to us with a box of chocolates) and forget our failures ( who move on to another doctor !)

'Our brains seem to be hard-wired for anecdotes, and we learn most easily through compelling stories; but I am aghast that so many people, including quite a number of my friends, cannot see the pitfalls in this approach. Science knows that anecdotes and personal experiences can be fatally misleading. It requires results that are testable and repeatable. Medicine, on the other hand, can only take science so far. There is too much human variability to be sure about anything very much when it comes to individual patients, so yes there is often a great deal of room for hunch. But let us be clear about the boundaries, for if we stray over them the essence of science is quickly betrayed: corners get cut and facts and opinions intermingle until we find it hard
to distinguish one from the other.’

Ross N. Foreword. In: Ernst E, ed. Healing, hype, or harm? A critical analysis of complementary or alternative medicine. Exeter: Societas, 2008:vi-vii.

http://www.testingtreatments.org/tt-main-text/thumbnails/background/anedotes-are-anecdotes/