Dr. Brad Roter, the Seattle physician who authorized Garon's pot use for nausea, abdominal pain and to stimulate his appetite, said he did not know it would be such a hurdle if Garon were to need a transplant.

That's typically the case, said Peggy Stewart, a clinical social worker on the liver transplant team at UCLA who has researched the issue. "There needs to be some kind of national eligibility criteria," she said.

The patients "are trusting their physician to do the right thing. The physician prescribes marijuana, they take the marijuana, and they are shocked that this is now the end result," she said.

No one tracks how many patients are denied transplants over medical marijuana use.

Pro-marijuana groups have cited a handful of cases, including at least two patient deaths, in Oregon and California, since the mid- to late 1990s, when states began adopting medical marijuana laws.

Many doctors agree that using marijuana — smoking it, especially — is out of the question post-transplant.

The drugs patients take to help their bodies accept a new organ increase the risk of aspergillosis, a frequently fatal infection caused by a common mold found in marijuana and tobacco.

But there's little information on whether using marijuana is a problem before the transplant, said Dr. Emily Blumberg, an infectious disease specialist who works with transplant patients at the University of Pennsylvania Hospital.

Further complicating matters, Blumberg said, is that some insurers require proof of abstinence, such as drug tests, before they'll agree to pay for transplants.

Dr. Jorge Reyes, a liver transplant surgeon at the UW Medical Center, said that while medical marijuana use isn't in itself a sign of substance abuse, it must be evaluated in the context of each patient.

"The concern is that patients who have been using it will not be able to stop," Reyes said.

Dale Gieringer, state coordinator for the California chapter of NORML, the National Organization for the Reform of Marijuana Laws, scoffed at that notion.

"Everyone agrees that marijuana is the least habit-forming of all the recreational drugs, including alcohol," Gieringer said. "And unlike a lot of prescription medications, it's nontoxic to the liver."

Reyes and other UW officials declined to discuss Garon's case.

But Reyes said that in addition to medical concerns, transplant committees — which often include surgeons, social workers and nutritionists — must evaluate whether patients have the support and psychiatric health to cope with a complex post-operative regimen for the rest of their lives.

Garon, the lead singer for Nearly Dan, a Steely Dan cover-band, remains charged with manufacturing marijuana. He insists he was following the state law, which limits patients to a "60-day supply" but doesn't define that amount.

"He's just a fantastic musician, and he's a great guy," said his girlfriend, Leisa Bueno. "I wish there was something we could do legally. ... I'm going to miss him terribly if he passes."