Grant Krieger, speaking to reporters outside a Calgary courthouse in 2000, signed a legal document Tuesday pledging to stop growing or distributing marijuana. (Adrian Wyld/Canadian Press)

A longtime advocate for the use of medical marijuana has agreed to give up a fight that has seen him battle the justice system as far as the Supreme Court of Canada.

Grant Krieger, 54, who has for years vocally defended his right to provide marijuana to the sick, signed a legal document Tuesday pledging to stop growing or distributing it.

"I've hit the end of all my ropes, and I'm just tired of it now," he said in Calgary.

Krieger uses marijuana himself to treat symptoms of progressive multiple sclerosis. At one time, he also supplied more than 400 sick people with the drug through a compassion club.

As a result of Krieger's promise, Alberta's Court of Appeal has swapped a four-month jail sentence for 18 months of probation in a 2007 trafficking conviction.

Krieger was at first given jail time because he "stated he did not think he had done anything wrong and had no intention of closing his club (and) and confirmed that he would not desist from his campaign to distribute marijuana," the appeal decision reads.

That stand was the continuation of a campaign that saw him defiant in court case after court case from his first trafficking conviction more than a decade ago.

He took one case all the way to the Supreme Court, where he was granted a new trial after the court ruled the trial judge had erred by directing the jury to find him guilty.

Krieger admitted Tuesday that he could no longer keep up the fight.

"It's taken 13 years out of my life, destroyed my family, removed my driver's licence," he said. "It's cost me a phenomenal amount of money. I'm in hock up to my eyeballs."

Says he'll turn to black market

Krieger maintains the federal government's medicinal marijuana program is a joke. He refuses to use their marijuana himself, saying it's grown in a dirty mine shaft and irradiated.

It's next to impossible for most sick people to even have the option, he said, as doctors are extremely reluctant to sign off on the therapy. And although he technically has the federal government's permission to use marijuana legally as a treatment, he said has been backed into a corner.

'I want to get on with the rest of my life, no matter how long it might be.'—Grant Krieger

He said he'll now buy the drug — which enables him to continue to walk and function despite his debilitating disease — "on the black market, like everybody else."

Krieger's cause is often confused with those who wish to legalize marijuana altogether, said his lawyer, John Hooker.

His client, however, was only interested in helping people who were legitimately ill and had safeguards in place to make sure the marijuana was not used recreationally, he said.

The appeal court ruled Krieger "made no financial gain, so was not motivated by profit but by concerns for others' suffering," but it said that's not enough of a justification.

Krieger is still facing sentencing in one outstanding trafficking case in Winnipeg.

"I want to get on with the rest of my life, no matter how long it might be."