Doctors once knowingly prescribed placebo pills to their patients before modern pharmaceuticals existed to help them.

At the Mount Auburn Cemetery in Cambridge, MA, Alan stands among hundreds of graves. Many of them belong to children and adults in their 30s and 40s who died before medical doctors had useful tools against common bacterial diseases like cholera and tuberculosis. But that didn't stop doctors from ministering to their patients. In "Intro segment," Alan asks Charles Rosenberg and Anne Harrington -both medical historians from Harvard University - what kept doctors in business.

Rosenberg shows Alan a medical manual, The English Physician Enlarged, published in 1656. The book lists some 369 herbal remedies for a wide range of ailments. Perhaps the most impressive herb was one known as "Hercules Allheal," which could -according to the manual - heal everything from gout to toothaches. Did it really work?

Until the 20th century the history of medicine is the history of the placebo effect. "We are exquisitely attuned to help from other human beings," says Harrington

While the herbs cited in The English Physician Enlarged may have had some physiological affect on the body - such as making the pulse race - it's unlikely that many of them actually cured any diseases. But, says Charles Rosenberg, "People always expected if they were sick to take a drug."

And that's where the placebo effect comes in. When people expect to feel better, they often do. Doctors, shamans and other healers around the world and throughout history have both knowingly and unknowingly used the placebo effect to their advantage. Today, scientists are teasing apart the mystery of the placebo effect in the hopes of adding its power to the arsenal of modern medicine.

For more on this topic, see the web feature:
Coincidental Cures