The 32-year-old mother of two was diagnosed with Ewing sarcoma in 2014. After a year-and-a-half in remission the cancer came back.

"It's heartbreaking, but the sad reality is this is not something I'm going to get over. It's more how long can I keep going," she said.

Her two children, Ava,4, and Ashton, 3, know little of the intense waves of nausea and violent vomiting episodes their mother suffers during and after her chemotherapy cycles.

"They know mummy's sick, and mummy has no hair, and mummy goes away to get medicine but we don't used the cancer word at all at home. They're too young and what they do know is scary enough," she said.

Mrs Hew is stoic as she describes being hospitalised after almost every chemotherapy session, vomiting blood with bouts so violent they burn her oesophagus, and being so dehydrated she fainted and hit her head.

"The side effect from chemo are horrible. That doesn't come anywhere near to explaining how bad it is," she said.

"I watch everyone else around me crumble at times. There's no point me lying down and crumbling too.

"I need my children to remember me as a happy mum that did things with them and took them to the park and the zoo while I'm here, because if things get worse I won't get to do that with them," she said.

The primary school teacher from Marsfield is hoping she will be screened for a world-first clinical trial of medicinal cannabis to treat cancer patients with severe nausea and vomiting caused by chemotherapy.

The randomised, placebo-controlled, double-blinded trial will test whether cannabis in the form of an oral, plant-derived capsule could be a safe and effective treatment.

Doctor have begun recruiting patients for the pioneering initiative championed by the NSW government, which aims to enrol more than 300 chemotherapy patients who do not respond to anti-nausea medication.

Some 80 patients will be recruited for in stage one of the trial conducted by the Chris O'Brien Lifehouse, in partnership with the University of Sydney, the Royal Prince Alfred Hospital and other major NSW cancer centres.

An additional 250 patients enrolled in stage two from across the state, the Centre for Medicinal Cannabis Research and Innovation advised.

The pharmaceutical grade capsules developed by Canadian company Tilray contain consistent doses of Cannabidiol (CBD) and minimises the amount of delta-9-Tetrahydrocannabinol (THC) - the component of cannabis that causes the 'stoned' effect.

There was little in the way of high-quality research internationally on the role of cannabis to treat nausea and vomiting caused by chemotherapy, the study's lead researchers Associate Professor Peter Grimison said.

"We have come a long way with conventional anti-nausea medication, but one-third of patients continue to suffer during and after chemotherapy, said Associate Professor Grimison at the Chris O'Brien Lifehouse.

"The role of cannabis medicines in alleviating chemotherapy-induced nausea and vomiting is still unclear, and this study aims to provide a definitive answer to this question," he said.

Minister for Medical Research Pru Goward said a rigorous, evidence-based approach with a pharmaceutical grade [substance] was the only way to definitively demonstrate whether cannabis could be a safe and effective treatment for these patients.

"The trial will play a critical role in developing a better understanding of how cannabis products may provide relief for cancer patients," Ms Goward said.

"It's amazing to think that people have been talking about this for 30 years and yet there has been no real investment in putting it up. It's come down to NSW to be a world leader, " Ms Goward said of the state government's $21 million funding for medicinal cannabis clinical trials and reforms.

"I am just hopeful this will make the difference so many people claim it will make. It's time to get to the bottom of it," Ms Goward said.

"These patients often lose a phenomenal amount of weight through the vomiting and the nausea. They're often very very sick, and this is a time they really need their strength.

"I hate the word courage, it's often overused but you can't deny it describes these patients. They are so hopeful.

Mrs Hew is prepared for whatever the results of the trial.

"Even if it doesn't work for me," Mrs Hew said. "It will be enough to know I was part of the trial and to know it could work for someone else."

"It's an opportunity that, right now, I don't have."

Fairfax Media has partnered with the Global Drug Survey for its fifth year to help understand how and why people take drugs in Australia.

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