Tara Stiles, founder of Strala Yoga in Manhattan, needs no introduction. Her first "how-to" yoga guide, Slim, Calm Sexy , which proposed a breezy merger of yoga, fashion, and "grrrl power," earned her a flattering profile in the New York Times. Since then, she's emerged as one of yoga's most instantly recognizable celebrities -- "yogilebrities" to critics -- and perhaps its highest-paid corporate mascot . Stiles' second book, Yoga Cures (New York: Random House, 2012), for which her new-found collaborator, New Age guru Deepak Chopra wrote the Preface, was released last year with its first printing in paperback, presumably to rapidly expand distribution. Like her first book, it's filled with photographs of the 31-year-old Illinois native -- who sometimes depicts herself as a "small-town Midwestern girl" -- displaying her usual blend of physical grace and calisthenic prowess in every yoga pose imaginable.

But this time Stiles isn't just selling readers on the cosmetic, fitness or stress relief benefits of yoga. She's also going where no yogi has gone before: boldly arguing that specific sets of yoga poses can provide serious healing and relief -- indeed, a veritable "cure" -- for a wide range of physical "ailments," some of them serious, like glaucoma and high blood pressure, and others, such as a hangover after a heavy night of drinking, or "jiggly thighs," almost trivial, by comparison.

Even on its face, the quasi-medical case Stiles tries to make strikes this reader as facile -- and unconvincing. Her "scientific" method -- if it can even be called that -- consists largely of describing a medical condition in general terms, then pointing to a single published study that broadly hints that yoga might provide some relief. Stiles sometimes hedges, and doesn't actually use the term "cure." In fact, the closer you read her book, the more you wonder whether Stiles is actually promising much of anything at all. What she does offer are suggestions for specific yoga poses that naturally work on body areas or functions implicated in a specific affliction. But that's about it. Does she actually provide real "evidence" -- even anecdotal, based on her own experience or that of her students -- that the specific asanas she promotes will actually heal specific afflictions? Shockingly, she doesn't even try.

In fact, Stiles doesn't even link the demonstrably weak "science" contained in the studies she selectively cites -- most of them based on small and unreliable "convenience' samples -- to the yoga poses that she advocates. When she cites a study that claims that yoga helped with a specific condition, it's not at all clear what kind of yoga -- or really how much -- was practiced by study participants. Was it even remotely comparable to the poses she endorses in the book? She doesn't tell us. (I suspect she doesn't know.) Even worse, in most of these studies -- some of them published in the academic equivalent of Siberia -- the experimental "control" group -- if the study even had one -- that wasn't exposed to yoga did virtually nothing else instead. That means, in most cases, it's impossible to know whether the yoga tested in the study would be more effective than a different treatment -- stretching exercises , tai-chi , therapeutic massage, or simple medication, for example -- might be.

Another troubling aspect of Stiles' book is how often she "prescribes" potentially dangerous or high-risk yoga poses like the plow, shoulder stand, and headstand for a wide range of ailments. Science reporter William Broad and a growing number of professional yoga trainers, including Michaelle Edwards and Victoria McColm , have recommended that these "inversion" poses be scaled back -- or not performed at all -- citing the threat of severe neck injury or even a stroke (through extreme compression of the carotid artery). Stiles sounds blithely unaware of this ongoing controversy and even offers up these same extreme poses as her primary treatment for everything from hyperthyroidism and the common cold to dizziness and yes -- believe it or not -- wrinkles. (Apparently, a Stiles headstand is so powerful it can lessen your need for makeup, to say nothing of a cosmetic surgeon).

Equally troubling -- given the state of the actual evidence -- is Stiles' suggestion that yoga is so powerfully healing that it might substitute for other treatments, even doctor-prescribed medication. For example, on the topic of ADHD, she points only vaguely to "studies" that suggest that yoga might be an effective treatment -- but she doesn't actually cite any of these studies by name. In fact, those ADHD studies I am aware of -- for example, some recently reviewed by the trade magazine Yoga Journal -- do find that yoga could have a calming effect, but they don't recommend that ADHD sufferers abandon their medication -- far from it. Stiles frequently tries to cover her back by noting that people with serious medical conditions should "always consult their doctor." That's all well and good, but for ailment after ailment -- including serious ones like hyperthyroidism and glaucoma -- she clearly implies -- irresponsibly, in my view -- that a regular and rigorous yoga practice alone -- preferably her own, of course -- might well do the trick. A more modest -- and medically sound approach -- might merely point to yoga as a natural "complement" to other treatments and mind-body approaches, pending more serious research.

Arguably, Yoga Cures does make a good case for thinking about yoga as a healing modality rather than just a fitness regimen or a weight-loss program. For yoga newbies, that may be its main redeeming virtue. But Stiles, with Chopra's eager support -- and perhaps, under pressure from her publishers -- proceeds to undermine her credibility by indulging in the worst kind of marketing hype. Despite an early disclaimer that she's not offering "medical advice, "Yoga Cures, by omission and inference, comes disturbingly close -- way too close -- to doing just that. The book strains credulity -- and good judgment -- further by lumping together serious diseases and illnesses with passing medical annoyances, which only seems to make yoga sound like something akin to snake oil. And implying that sufferers might somehow throw a handful of yoga asanas, especially risky ones, at such a disparate range of conditions (who wants to do an unassisted headstand for a cold?) -- and they'll magically disappear -- seems like flat-out medical quackery.

How is a former classical ballet dancer in a position to advance such claims? She isn't really -- at least not alone. That's where her erstwhile collaborator, Chopra, an M.D. in "holistic" medicine and self-styled yoga philosopher, plays such a critical supporting role, by lending intellectual heft -- and a vaguely Hindu aura -- to Stiles' efforts. The two have begun collaborating in earnest, and have even started to co-brand some of their yoga offerings. In the book's Preface, Chopra goes even further than Stiles does in extolling yoga's application to a wide range of illnesses, periodically throwing in the caveat that "more research is needed." But Chopra doesn't actually have a background in bio-mechanics, kenesiology, or other sciences that might allow him to formally vouch for Stiles asana approach or for the research she cites (in all likelihood, Chopra himself wrote or edited her research review). This is just one more example of how marketing hype and wishful thinking about yoga's alleged curative powers can be given the hallowed status of "science."

Bringing yoga and professional medicine together in greater harmony and bliss is a noble goal. But given the actual state of the evidence for yoga's ability to address and heal specific conditions, Yoga Cures is a shotgun marriage at best. Consumers do need intelligent science-based advice, and they need to practice yoga in conjunction with other activities in ways that are safe and helpful. They also need a balanced assessment of the areas where yoga can actually help them heal, not a biased review that actually conceals research -- on arthritis , for example, another area Stiles cites -- where the evidence is at best, mixed. The last thing consumers need to be told, or to infer, is that yoga -- or anything else for that matter -- is a divinely-inspired wonder drug, and that like a cripple lying prostrate before a faith healer, they might throw away their crutches, rise up, and walk again.