A Saskatoon doctor says medical professionals have some questions about the changes to medical marijuana rules in the country.

As of Wednesday, Canadians who have a doctor's approval can grow their own medical pot or have someone else grow it for them.

Under the new rules, doctors now provide "approval letters" instead of prescriptions.

Dr. Ryan Meili, who teaches at the University of Saskatchewan medical school said he is worried patients will not be getting the right dosage of tetrahydrocannabinol or THC, which is the active ingredient in marijuana.

"It's not entirely clear what people are getting when they purchase from some of these products, if they are getting THC at the right level, at the level that would be the most therapeutic," he said.

"There is talk of people sort of getting talked up to higher doses."

Meili said the government needs to remember that people can get addicted to pot and needs to have sufficient addiction treatment available to those who will need it.

Next spring, recreational marijuana is also set to be legalized across the country.

"We need to also recognize that it is not an entirely benign thing for people to be taking," Meili said. "You get addiction, people having serious problems in their lives."