Researchers at Harvard University say the treatment killed all the tumour cells in 70 per cent of mice with pancreatic cancer - a cancer that kills 93 per cent of its sufferers within five years.
Pancreatic cancer is one of the hardest to treat forms of the deadly disease, but scientists have discovered that flavonids - the compounds present in the majority of plants that give them their vibrant colours - could hold an answer.
Flavonids are neither a cannaboid, nor a psychoactive component - setting them apart from the more regularly consumed forms of cannabis like CBD oil or marijuana-infused foods.
There are more than 6,000 variations of flavonoids but the Harvard scientists see great potential in one found in cannabis and used to make a compound dubbed FBL-03G.
Although it's not the first time cannabis has been used as a cancer treatment, the drug is more traditionally used to ease unpleasant side-effects of standard cancer therapies like chemo and radiation.
However, recently cannabis has been used in a slew of studies exploring the plant's potential for treating cancer itself.
The Harvard team say they need to investigate their miracle find further before any concrete claims can be made.
"People have done studies before showing that sometimes cannabis works against cancer, and sometimes it doesn't," co-author of the new Harvard study, Dr.Wilfred Ngwa said.
He attributes a lot of these discrepancies to the wide variation in the composition of any given cannabis strain or plant and lack of consistency in this sense from study to study.
"So maybe the plant we're investigating in Boston is very different from what we're investigating in California," Dr.Ngwa says.
Of the flavonoid tests, Dr.Ngwa says: "We were very surprised with the results we got."
"We expected it to to show some inhibition of tumor growth, but we were quite surprised that it also inhibited tumor progression in other parts of the body.
"We actually had to run some additional measurements to see if this was really true."
It's unclear if the cancer might return, but for the time being, the majority of the mice were cancer free.
Dr.Ngwa and his team aren't exactly sure how the flavonoid treatment works, but says he is "fairly confident" that there are active, anti-cancer components in cannabis, but that "each cannabis plant produces completely different levels of active components."
The doctor and his team say they are conducting further research into the miracle find, and for the time being "patients 'need some patience."