Under armed guard, at a secret location in the hills of northern Israel, rows of cannabis plants in a large greenhouse give off a sweet, distinctive smell.
In a nearby processing room, bags of dried buds and leaves are weighed and bagged. A woman in a lab coat operates a device producing dozens of ready-made cigarettes.
Cannabis is an illegal drug in Israel but this facility is allowed to operate under a government licence.
The company that runs it, Tikun Olam, uses organic methods to grow different kinds of cannabis for medical use.
Now, it has developed a new strain that could change the image of the drug.
It does not give users the characteristic high or get them "stoned".
Careful cross-breeding has virtually removed the chemical in cannabis known as THC (tetrahydrocannabinol), which has psychoactive properties.
Instead the new plant has a high concentration of another of the main constituents called cannabidiol (CBD), a powerful anti-inflammatory.
"Cannabidiol does not bind to the brain, to the brain cells, therefore after taking it you don't have any side effects that you don't want," says Ruth Gallily, an immunology professor at Hebrew University who has researched CBD for 15 years.
"(These include) not being high, not being confused. You can drive, you can work, you can do everyday things. It's very non-toxic."
Tikun Olam's research and development manager, Zach Klein, lists the categories of patients who can benefit from the new product.
"The new strains are really good for three populations - people who work, old people - because they are sensitive to THC - and also children, as we want to touch those receptors in their brains as little as possible," he says.
David Sabach, 12, suffers from cancer but has just been out playing with friends when I visit his family's apartment in central Israel.
He shows me pictures of how he looked two years ago. He had lost his hair from chemotherapy treatment and was half his current weight.
A doctor recently prescribed David the CBD-enriched cannabis. It is delivered in the form of chocolate, cookies or cakes.
"I used to take morphine for pain and it would help for just a couple of minutes," he tells me.
"When I take the cannabis it helps me all day. I feel much better. I can finally walk without crying from the pain in my legs."
Medical marijuana has been used in Israel since the 1990s.
More than 10,000 Israelis take it to treat a range of illnesses from cancer, Parkinson's disease and multiple sclerosis to Tourette's syndrome.
Many believe it is the combination of THC and CBD in regular cannabis that is most beneficial. THC has its own medicinal effects.
"It shouldn't be changed. This is nature's medicine and it's been used for thousands of years," says a 52-year-old cancer patient from Tel Aviv who does not want to be identified.
He had a stomach tumour removed five months ago and smokes cannabis while undergoing chemotherapy.
"Mostly it helps with pain reduction. The second thing is the desire to eat. The body without fuel cannot fight and one of the wonderful things about marijuana is that it causes "munchies", and "munchies" for people during chemotherapy is a blessing."
The exact properties of the dozens of cannabinoids contained in cannabis and their interactions are still being studied.
International pharmaceutical companies are experimenting with the ratio, and developing synthetic versions, to use as medicines.
However, growers say traditional horticultural techniques also have potential to create tailor-made cannabis for different conditions.
The new "high-free" Israeli version could also challenge the ban on medical uses of cannabis currently enforced in many countries.