"We managed to isolate the molecules of THC and CBD," said Mor Cohen, head of the growing facility on the edge of the Galilee town of Safed, referring to cannabidiol, another component of cannabis, which can help ease symptoms of diabetes and some psychiatric disorders.

While the small family-based firm has developed a variety that is over 99 per cent CBD, it has also cross-bred it with other varieties to give plants with different mixes of the two ingredients, aimed at helping patients with differing needs.

Getting the balance right, they say, can ease pain and stimulate appetite, while reducing or eliminating unwanted effects.

"We have accumulated experience in treatment of some 2,000 patients with varying symptoms; some with pain, others with constipation, dizziness or nausea," Cohen said inside a vast tented enclosure with row upon row of plants giving off a heady, sickly sweet perfume.

"We know how to provide a solution, whether it's for Parkinson's disease, for cancer, to increase appetite, problems of insomnia related to post-traumatic stress disorder … for each and every illness."

"THC is the substance that stimulates appetite," said Tzahi Klein, head of development. "CBD acts differently. For some people THC has unwanted effects, but CBD reduces the psychoactive activity of the THC.

"We have a range of plant varieties from full THC to a very high proportion of CBD, and we can suit the relative percentages to different patients."

Information Minister Yuli Edelstein, while supportive of medical marijuana in general, and the work of Tikkun Olam in particular, said the government was not considering blanket legalisation of cannabis use.

"The new thing here is that what has always been thought of as just a drug, a negative thing, has become - through the good work of the growers here - a medicine which in fact is not a narcotic," he said on a visit to the site. "We are not dealing at the moment with the legalisation of marijuana."