Medical marijuana users say Ottawa is trying to take away their "God-given right" to grow cannabis to relieve pain symptoms.

Groups opposed to the federal government's new medical-marijuana regulations, which go into effect today, are protesting on Parliament Hill.

The demonstration comes one day after Ottawa said it would challenge a Federal Court injunction that allows medical users to continue growing their own pot pending a constitutional challenge of the new rules.

The new regulations require marijuana users to receive their supply from commercial growers, and also limit the amount that individuals are allowed to possess.

Critics say the new rules will simply make it harder for them to access a drug many of them insist they can't live without.

Alison Myrden, who suffers from chronic progressive multiple sclerosis, says she relies on medical pot every single day. Myrden says the new regulations would mean a substantial increase in the cost of the drug, and potentially create supply problems as well.

Unclear when appeal of injunction will be heard

It is unclear when the federal appeal of the injunction will be heard.

If the government ultimately fails to overturn the Federal Court decision, it will leave the path clear for the constitutional challenge. As a result, the matter could be tied up in the courts for many months to come.

The number of people authorized to possess — and frequently grow — marijuana under the old federal program climbed to 37,000 this year from fewer than 100 in 2001.

Several patients permitted to cultivate their own pot, or serve as a designated grower for someone else, say the planned new system denies ill Canadians a safe, affordable supply of medical marijuana.

Some say they can grow at home for pennies a gram, while official suppliers licensed by Health Canada charge anywhere from a discounted price of $3 a gram to as much as $13.50.

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