One of the most clinically knowledgeable physicians on medicinal cannabis in the US is giving two talks in the region.

Dr David Bearman will be in Nelson on Saturday and Golden Bay on Monday with, "Medicinal Use of Cannabis, What can New Zealand Learn?"

The expert speaker and author has made hundreds of presentations to professional and lay audiences on medical marijuana, drug abuse treatment and prevention, and the origins of American drug policy.

Victoria Catherwood is a fifth-year medical student and co-organiser of Dr Bearman's New Zealand tour.

Fifth-year Otago University medical student Victoria Catherwood is the driving force behind the visit.

She has been a medical marijuana campaigner since witnessing her terminally-ill mother's "extraordinary and miraculous" changes after using cannabis to treat the pain resulting from aggressive tumours.

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Marion Van Dijk/Fairfax NZ Nelson lawyer Sue Grey said Dr Bearman's talks were a "huge opportunity" learn about how the medicinal cannabis system was working overseas and how it might benefit New Zealand.

Catherwood has been crowd funding to produce a documentary for medical professionals on the benefits of marijuana and she also runs a private Facebook group called Medical Students for Medicinal Cannabis that has 190 members.​

Catherwood said that because of its illegal status, New Zealand doctors and medical students do not receive any education on medicinal cannabis.

"The first and most important reason for Dr Bearman's visit is to bring an expert doctor to show the medical world that the research is there, so they will stop using this archaic lie that there's no research," she said.

"The other main reason is to help the politicians make the right law changes and show them there is evidence that works."

Catherwood said a med student like her didn't have much power — "but an expert like Bearman does".

She said the endocannabinoid system was one of the largest neurotransmitter systems in the bodies and was found in most mammals.

The cannabis plant helped by calming the the nervous and immune systems by mimicking what the endocannabinoid system naturally does in regulating mood, sleep, pain, motor control, immune function and appetite.

It helped with pain management, motor-control, epilepsy, post-traumatic stress disorder, ADHD, autism and IBS.

During his New Zealand tour, Catherwood said Bearman will give four talks around the country, discuss medical cannabis and law reform at a round table with politicians, and present at the Grand Round Christchurch Hospital.

Golden Bay medicinal cannabis advocate and tour co-organiser, Victoria Davis, said she hoped the talks would offer its audiences a realistic look at the uses of the cannabis plant.

"I think we are going to see a lot of caregivers who are coming along that are curious about what they can expect when they finally legalise it."

Nelson Lawyer Sue Grey said it was a "huge opportunity" for doctors, patients, politicians, lawyers and anyone else who might be interested to learn about how the medicinal cannabis system was working overseas and how they might benefit.

"I see this as huge step forward because one of the limitations is that our doctors in New Zealand don't learn about the endocannabinoid system," she said.

"This turns out to be a really important part for our bodily functions, and it stabilises the immune and nervous systems, by offering them rest. This explains why it works for so many chronic conditions."

Bearman will give talks with Q&A in Christchurch, Wellington, Nelson and Golden Bay.