eah Grove said "inhalation therapy" felt like riding a magic carpet. Perhaps that's why she continued the treatment in the face of common sense—and her own violent physical reaction. She would thrash, shake, and gasp for breath as her psychiatrist, a 73-year-old named James Watt, held a mask to her face and began administering the combination of gases that was supposed to help her recover repressed childhood memories. Twice, the 38-year-old computer sales executive threw up immediately after the sessions. On one occasion, Grove even punched Watt in the face, which led him to suggest that she bring someone along to the appointments to help restrain her.

And so it was that Kevin O'Brien, who was living with Grove at the time, ended up in Watt's East 46th Street office on a mild afternoon last April, straddling his girlfriend's knees and holding her arms while the doctor held the mask over her face, cranked up the dial attached to it, and administered a combination of oxygen, carbon dioxide, and nitrous oxide that sent her into a twilight state.

Sometimes Grove saw geometric shapes in this netherworld—visions of icicles that would shatter and re-form into mosaic patterns. Watt, who could not be reached for this story, had said his $150-per-session treatments might also bring back her buried past—and, with it, a cure for Grove's mild depression, which had resisted both Zoloft and talk therapy for years. It was his desire to help his girlfriend in this quest, O'Brien says now, that convinced him to use his 175-pound frame to pin Grove down that day.

O'Brien's heft didn't turn out to be necessary. Grove did struggle for breath, but after writhing briefly, she became eerily still. "It was different from the other times," remembers O'Brien, who had acted as bodily restraint in at least six previous sessions and was planning to try the therapy himself that afternoon. "She just stopped responding. Something was wrong." Grove never regained consciousness. After being in a coma for three weeks, she died.

Eleven months later, O'Brien inhabits a nightmare world of his own. He is convinced James Watt is responsible for the death of the woman he loved. He feels Watt, a medical professional, should have known that too much of either carbon dioxide or nitrous oxide could suffocate Grove. O'Brien saw it happen. He felt Leah Grove lose the force of life while he held her in his arms. And he is convinced Watt committed a crime. But he has yet to bring the doctor to justice.

O'Brien has had a hard time just getting anyone to listen to his story. While Grove was still in a coma, he quit his public relations job to devote himself full-time to his obsession with holding Watt accountable. He's been interviewed by the Manhattan district attorney's office twice and has badgered the prosecutors so often they no longer return his calls. (The D.A.'s office says it has been responsive.) In the desperate hope that it would force the D.A. to take action, O'Brien set up a Web site detailing the circumstances of Grove's death and began bombarding local newsrooms with his press releases.

Meanwhile, Watt, who was already semi-retired before the incident and has since moved to Texas, seems likely to remain free. In recent weeks, O'Brien has been waiting with bated breath for final word from the D.A. According to a recent report in the New York Post, the doctor is poised to strike a bargain with the prosecutor's office that would allow him to serve no jail time for Grove's death in exchange for pleading guilty to a charge of criminally negligent homicide. Sherry Hunter, a spokesperson for the Manhattan D.A., confirmed that the office was investigating Watt, but wouldn't comment further on the case.

"He's going to walk!" says an outraged O'Brien. "How can they let him walk?"

Similar questions plague countless other survivors. Though only the most scandalous cases hit the papers, advocates say many more egregious medical acts go unrecognized—and unpunished. "What we see is just the tip of the iceberg," says Ralph Speken, a physician who was unable to convince the authorities to pursue a criminal case after his 23-year-old son, Seth, died while being restrained in a New York City hospital in 1993. The doctor has since devoted himself to getting the criminal justice system more involved in medical misconduct.

No one knows for sure how many deaths and injuries are the fault of bad doctors. According to a 1999 report issued by the Institute of Medicine, a Washington-based organization that provides information on health and science policy to the government, between 44,000 and 98,000 people die in the United States every year as a result of medical errors. Studies of physician disability are one gauge of how many doctors should be disciplined for their behavior. According to the Foundation of the Pennsylvania Medical Society, some 5 to 10 percent of physicians are disabled by either drug or alcohol use, mental health problems, or physical illness to the point where their work is impaired. Since New York State has 57,000 practicing physicians, that means that up to 5700 doctors in New York may be affected.

But in New York City, there have apparently been no criminal convictions for harm caused by bad medicine since 1995, when David Benjamin, a Queens physician, was convicted of manslaughter for the death of a woman in a botched abortion. And during 2000, the last year for which statistics are available, the New York State Department of Health Office of Professional Medical Conduct (OPMC), which is responsible for investigating physician misconduct, took only 411 actions of any kind. In 144 of those, the doctors lost their licenses.

Why are the numbers so low? "There's a wall of silence," says Arthur Levin, director of the Center for Medical Consumers, a public-interest advocacy organization. "It's just like with the police. There's a brotherhood that doesn't feel comfortable most of the time reporting misconduct."

Doctors may be also getting off free because of the baffling system for patient redress, which consists of three disconnected entities—the civil courts for malpractice suits, the state's disciplinary board, and the criminal courts. "The process is so confusing for victims," says Ilene Corina, president of Pulse of New York, a nonprofit that's dedicated to supporting people harmed by the medical system. Corina experienced the confusion first-hand when her three-year-old son died after a tonsillectomy in 1990. Though Corina knew "the doctor had screwed up," as she puts it, she didn't know where to file a complaint. Health department authorities never investigated the incident.

Corina is now extremely familiar with OPMC. Since Pulse formed three years ago, she has gotten hundreds of calls—at least 50 of which she estimates involved patients who died in New York State. Corina instructs many of these desperate callers how to file a complaint, but she says that those who follow her advice often get no satisfaction. "Three-quarters of the time they just get blow-off letters," says Corina, referring to the OPMC form letters that terminate cases by saying they didn't involve misconduct.

Indeed, bad doctors—even those who have been successfully sued for malpractice—frequently escape discipline by the state. "Negligence just doesn't get any sort of reaction from the board of medical examiners," says William Levinson, a malpractice attorney representing the estate of a New Jersey woman who died after a scientifically unproven treatment known as ultra-rapid opiate detoxification (UROD). Seven patients have died in the past five years after undergoing this unorthodox procedure, which is supposed to cure heroin addiction almost instantly. But though they've agreed to temporarily stop performing UROD, the doctors who provide it, Lance Gooberman and David Bradway, still have their medical licenses. (Adding to Levinson's outrage at the New Jersey board, Bradway, a former addict, obtained his medical license after having served prison time for manslaughter for injecting a lethal dose of a drug into a friend and then dumping his body in a ditch.)

Advocates say it's also remarkable that Manhattan doctor Nicholas Gonzalez can still hang out a shingle. After one of his former patients was diagnosed with uterine cancer, Gonzalez discouraged her from following through on her cancer specialist's advice, instead recommending dietary supplements and frequent coffee enemas. Though a jury awarded the patient $2.5 million in damages after the cancer spread to her spine and blinded her, Gonzalez never lost his medical license. Sentenced by the OPMC to two years of probation with a stipulation that he undergo retraining and do 200 hours of community service, Gonzalez continues to practice on East 36th Street in Manhattan, just 10 blocks from the old office of Dr. Watt.

"We do not hesitate to take action when we believe a doctor has committed professional misconduct," Kristine Smith, spokesperson for the state department of health, says in defense of the OPMC. In fact, OPMC took up Watt's case even before O'Brien filed a complaint. Less than two months after the incident, the regulators struck a deal with the psychiatrist, allowing him to keep his license on the condition that he never practice medicine in New York again. "We took the strongest action possible," says Smith. "What may be confusing," she adds, "is that the health department's authority is not as encompassing as many people might think."

It's true. State law forbids the office from sharing its information with prosecutors while it is investigating a doctor, permitting the office to talk to criminal prosecutors about a case only after it's over. The profession's disciplinarians have no say in getting even the worst cases into the criminal courts. District attorneys decide what rises to the level of criminality. In the vast majority of medical cases, however, the typical red flags for police investigators are missing.

Consider that, if a patient stops breathing in a doctor's office, emergency medical technicians may show up without police, who often begin criminal inquiries. And when she dies in the hospital, the autopsy is unlikely to be coded as a homicide. In Grove's case, both police and paramedics arrived after O'Brien called 911, and the district attorney did begin a criminal investigation. O'Brien can't prove it, but he suspects that Watt has been sheltered by an official presumption that as a doctor he was trying to do good—and that no matter how egregious, his mistakes couldn't be criminal.

Many insist that this assumption keeps prosecutors away from most medical cases in the first place. "The D.A. has a bias that all medical issues should just be handled medically," says Speken, the physician and patients' advocate. "It's been a very, very serious error in judgment."

Even "Dr. Zorro," a/k/a Allan Zarkin, the Manhattan obstetrician who carved his initials into his patient's belly, didn't end up serving time. (He pleaded guilty to first-degree assault and was sentenced to probation and had his license revoked.) And though the Manhattan D.A. began an investigation in the case of Lisa Smart, who died when her body was pumped full of fluid during a surgical procedure in which a medical-equipment salesman participated, the office never pursued a criminal case.

The rare exceptions to that rule are often abortion doctors, who are subject to unusually strict oversight due to the pressure from the right-to-life movement. In New York City, both of the most recent convictions of doctors were supported by a well-organized legal effort to criminally prosecute abortion doctors. David Benjamin, the Queens physician, was sentenced to 25-years-to-life in 1995 for allowing his patient to die after he tore her uterus during a botched abortion. A witness testified that he left her unattended for hours while she bled to death. Just two years before that, Abu Hayat, an East Village physician, was convicted of severing the arm of a fetus while performing an illegal abortion on a woman who was seven and a half months pregnant.

Many more doctors ought to be prosecuted, according to lawyers familiar with the medical terrain. "We see an awful lot of terrible medical things happening," says Robert Conason, an attorney who handles malpractice cases and is currently representing Amadou Diallo's mother in a civil suit against the city for police brutality. "Some definitely transcend negligence." Conason suggests that the Department of Health pick out extreme cases and refer them for criminal review, a method that is used in several other countries. The change, he says, would not only afford personal vindication, but also prevent future incidents: "These cases of gross misconduct will happen again if you don't [criminally prosecute] them."

And the horror stories may signal that less dramatic injustices are rampant. "These kinds of examples reveal how dysfunctional our system is," says the Center for Medical Consumers' Levin. "If we can't keep track of these extreme cases, how can we expect it to cope with the everyday smaller complaints?"

One way, newly available this year, is the health department's Web site (www.nydoctorprofile.com), which allows New Yorkers to look up legal actions taken against the state's doctors. But even that likely wouldn't have helped Grove, who never found out that the mild-mannered Watt had once been arrested for having mescaline and LSD on his yacht and that he had had his medical license revoked in California in 1972. The records detailing the reasons for the California Medical Board's action have since been destroyed. But Watt had been involved in LSD experimentation in California, claiming it induced memories in his patients.

Perhaps that information would have convinced Grove not to submit to the dangerous procedure. Perhaps not. She already had plenty of reason to question Watt, whose equipment was obviously aging and whose business card advertised several techniques on the unproven edge of medicine, including "anti-aging therapy," "environmental detoxification," "IV nutrient infusions," and "chelation therapy."

Since it was tried experimentally in the 1940s, inhalation therapy has been widely discredited and, besides Watt, may have had no current proponents. The most recent literature Watt could offer Grove was a 1950 medical text, Carbon Dioxide Therapy, and even the author of that book acknowledged his treatment might never make it into the medical mainstream.

The long-out-of-print book, which Grove had ordered online and borrowed from Watt, details a psychiatrist's experiments with having patients inhale the gas. Several, like Grove, reported seeing geometric patterns. Some said the gas-induced dream state brought them vivid recollections of past events; one seemed to be reliving attempted rapes when she went under. The book, which arrived at Grove's apartment after the fatal treatment, also mentions patients' violent reactions to carbon dioxide, including seizures, screaming, and fighting "with tooth and nail."

Such resistance, not unlike Grove's, is also uncannily similar to the life-and-death struggle of a patient of another unorthodox treatment. Candace Newmaker, a 10-year-old, died in Colorado two years ago while she was undergoing "rebirthing therapy," which was supposed to cure her emotional problems by bringing her back to the very beginning of childhood. Two professionals held Newmaker down while she screamed, gasped, and, ultimately, suffocated. Both are now serving 16-year sentences for reckless child abuse resulting in death. Neither was a doctor.

It's hard to imagine why anyone would submit to such an ordeal. O'Brien says Leah Grove's decision to get "inhalation therapy" from James Watt boiled down to a simple desire to feel better—and perhaps a bit of unfortunate naïveté. "Watt was her doctor," says O'Brien. "She trusted him."