Unlike humans, rats can’t vomit.

But that didn’t stop researchers from using the rodents in a study that laid the groundwork for understanding how a cannabis component that doesn’t get you high could eliminate nausea for cancer patients going through chemotherapy.

The non-psychoactive component in pot, cannabidiol (CBD) can suppress the trigger for nausea, according to an academic paper published Tuesday by researchers at the University of Guelph and the University of Calgary.

Doctors already prescribe capsules of tetrahydrocannabinol (THC) – the psychoactive component in cannabis that give users a euphoric feeling – to treat chemotherapy-induced vomiting and nausea, but this is the first time CBD has shown potential to treat the symptoms, the authors say.

“The next step would be for somebody who does human clinical trails to pick up on this research,” said Linda Parker, a Canada research chair in behavioural neuroscience at the University of Guelph.

The research, published in the scientific journal eNeuro showed a nausea-inducing treatment in rats releases serotonin into the interoceptive insular cortex – the region of the brain associated with vomiting in both rat and humans – but an injection of CBD prevents the release.

“We had previous work that led to the hypothesis that this is what it’s going to do, but we didn’t have a direct measure of it,” said Parker, who authored a 2017 book on cannabinoids and the brain.

“Indeed, what we found was that the serotonin spike was prevented by pre-treatment with cannabidiol.”

The team also prevented serotonin’s release in rats by using a drug that raises levels of 2-AG, a cannabinoid produced naturally by the brain to reduce nausea symptoms.

Rats can’t vomit, but they have a gaping response that researchers measure to reflect nausea, Parker said.

Canada will become the first G7 country to legalize recreation marijuana – Uruguay is the only other country to do so – on Oct. 17.

Although cannabis has been prescribed for medical purposed for nearly two decades, little research has been done on its long- and short-term effects, nor have scientists fully explored the therapeutic potential of the more than 100 cannabinoids that make up the plant.

“We know so little about how it works,” Parker said. “We’re way behind. It will take many, many years – decades – to get to know what combination of cannabinoids will produce what effect.”