The New Zealand government should stop "lying" to its people over medicinal cannabis, a visiting doctor says.

United States physician Dr David Bearman, who specialises in medicinal cannabis effects and pain relief, said Associate Health Minister Peter Dunne needed some remedial education on cannabis.

"And he needs to stop talking out of both sides of his mouth. I don't see how on the one hand, he can say there's no evidence that cannabis is medicine and then on the other hand approve Sativex, which is tincture of cannabis — it's liquid cannabis."

Cannabis has been used as a medicine for over 4000 years and has been listed in every medical material ever written.

However, Dunne said Bearman's comments were inaccurate, ignorant, abusive and ill-informed.

"As such they are neither worth commenting upon further, nor taking in any way seriously."

Bearman said the people of New Zealand "need to understand that its government has been lying to them".



"Much the same as the US government has lied to the Americans. But fortunately for us, since 1997 we have been able to get more physicians to understand cannabis and the endocannabinoid system and help millions of people with a broad spectrum of diseases."

MONIQUE FORD/STUFF Associate Health Minister Peter Dunne has come in for some criticism and needs to smarten up on the health properties of cannabis, Bearman says.

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Bearman was in Nelson on Saturday and Golden Bay on Monday with his talk, "Medicinal Use of Cannabis, What can New Zealand Learn?"



Over 300 people in total attended the events in the Boathouse and Golden Bay Community Centre.



He also made a presentation in Wellington and Christchurch, and at the Christchurch hospital's grand rounds.



The expert speaker and author has treated thousands of people with medicinal cannabis in California for a wide-range of conditions.

He has also made hundreds of presentations to professional and lay audiences on medical marijuana, drug abuse treatment and prevention, and the origins of American drug policy.

It was critical New Zealand medical practitioners were educated on the the body's largest neurotransmitter system — the endocannabinoid system.

"In the States, only 13 per cent of medical schools teach about the endocannabinoid system. I would like to see all the medical schools in New Zealand institute a course on it."

The endocannabinoid system was important in terms of homeostasis, regulating our bodies and keeping us healthy.

He said the cannabis plant was so helpful because it slowed down the speed of neurotransmission, or the transfer of impulses between neurons.

"You can see how this would be helpful with migraine headaches, which is uncontrolled electrical stimulation of neurons in a specific area of the brain, and seizures is even more so. If you can slow that down, you can in many cases stop the migraine, and you can decrease the frequency and maybe eliminate seizures entirely."

There was a lot of science-based evidence and clinical evidence that cannabis was helpful in treating ulcerative colitis, a serious disease that often involves a partial removal of the bowel.

Bearman said cannabis has been used as a medicine for over 4000 years and has been listed in every Materia Medica ever written.

Hemp was also once the most profitable plant in the world, and the war on drugs was "all about money".

"The drug war has been an abysmal failure at an awful cost to the taxpayer and even greater cost to human life. And as a physician I would say — to human health."

He said the New Zealand government should start treating cannabis in reasonable way and stop forcing people to use a drug that costs $1400 a month.

"We should treat cannabis how we would treat any other medicine, and treat prescription medicines with the same aggressive scepticism that some of the authorities are treating cannabis," he said.

"I can't tell you the amount of people I have treated who were getting lists of drugs as long as my arm and they have all said, 'this has turned me into a zombie; and cannabis has helped me.'"