Paul Offit, MD, chief of Children’s Hospital’s Division of Infectious Diseases, has long been a magnet for controversy. A co-creator of the rotavirus vaccine Rotateq, Dr. Offit’s willingness to speak his mind has earned him many vocal critics over the years. For example, he has received hate mail and even death threats for working to debunk the now discredited connection between vaccines and autism.

In a move sure to earn him some new critics, Dr. Offit recently published a new book, Do You Believe in Magic?: The Sense and Nonsense of Alternative Medicine. In the book, Dr. Offit, who also directs CHOP’s Vaccine Education Center, examines the science and science fiction behind megavitamins, supplements, and alternative treatments like coffee enemas and laetrile.

Dr. Offit acknowledges that people often turn to alternative treatments after becoming disillusioned with conventional medicine. However, while “conventional therapies can be disappointing, alternative therapies shouldn’t be given a free pass,” Dr. Offit writes. This is because alternative medicine, as Dr. Offit points out, “can be quite harmful.”

And though many people think “excess vitamins can’t do any harm,” it turns out that “large quantities of supplemental vitamins can be quite harmful indeed,” Dr. Offit writes in The New York Times. In a recent op-ed, “Don’t Take Your Vitamins,” he notes excess amounts of vitamin E have been shown to increase the risk of heart failure and prostate cancer.

However, because megavitamins and other supplements are not regulated by the Food and Drug Administration, “consumers don’t know that taking megavitamins could increase their risk of cancer and heart disease and shorten their lives,” Dr. Offit writes. All therapies should therefore “be held to the same high standard of proof,” he notes in Do You Believe in Magic?

“Because the truth is, there’s no such thing as conventional or alternative or complementary or integrative of holistic medicine. There’s only medicine that works and medicine that doesn’t,” he says.