Like most TV shows, The Oprah Winfrey Show is entertaining as its first goal. And like most men, I've rarely enjoyed it much—because it's not aimed at me. That's fine.
But when she discusses health topics, Oprah can be dangerous (here's a single-page version of that long article). You have to infer from her show that on matters of health and medical science, Ms. Winfrey herself doesn't think critically, taking quackery just as seriously as, or more seriously than, anything with real evidence behind it. For every segment from Dr. Oz about eating better and getting more exercise, there seem to be several features on snake oil and magical remedies.
Vaccines supposedly causing autism, strange hormone therapy, offbeat cosmetic surgery, odious mystical crap like The Secret—she endorses them all. Yet even when the ones she tries herself don't seem to work for her, she doesn't backtrack or correct herself. And, almost pathologically, she remains obsessed with her weight despite all her other accomplishments.
Obviously, anyone who's taking their health advice solely from Oprah Winfrey, or any other entertainment personality, is making a mistake. However, I'd go further than that. Sure, watch Oprah for the personal life stories, the freakish tales, her homey demeanor, the cool-stuff giveaways if you want. But if she's dispensing health advice, ignore what she has to say. The evidence indicates to me that, while she may occasionally be onto something good, chances are she's promoting something ineffective or hazardous instead. Taking her advice is not worth the risk.