Medical cannabis use is associated with improvements in several common cancer-related symptoms, according to a new large-scale observational study.
Researchers at the Minnesota Office of Cannabis Management (OCM) analysed data from 6,621 people with cancer who purchased medical cannabis through the state programme between July 2015 and December 2023. The findings, published in the OCM report Impact of Medical Cannabis on Minnesota Cancer Patients, showed reductions in pain, nausea, vomiting, anxiety and depression. Improvements were also reported in sleep.
Patients completed self-assessments before purchasing cannabis, rating eight symptoms – anxiety, lack of appetite, depression, disturbed sleep, fatigue, nausea, pain and vomiting – on a scale of zero to ten. Researchers considered a reduction of at least 30% from a patient’s starting score to be a clinically meaningful improvement.
The strongest result was seen among patients experiencing vomiting. Of those who reported moderate to severe vomiting when they entered the programme, almost half (47.2%) recorded a clinically meaningful reduction in symptoms within four months of their first medical cannabis purchase.
Nausea also improved for 39.9% of patients who initially reported moderate to severe symptoms, while 38.2% experienced a meaningful improvement in lack of appetite.
Pain was the most common symptom among the group, with 82% of patients reporting moderate to severe pain when they joined the programme. Within four months of starting medical cannabis, 29.9% of those patients recorded a meaningful reduction in pain.
Among patients who experienced that initial improvement and remained in the programme long enough for further assessment, 53.1% maintained the reduction for at least another four months.
Around 40% of patients with moderate to severe anxiety reported improvement within four months, alongside 44% of those experiencing moderate to severe depression.
“Cannabis treatment appears relatively safe, and we now have strong observational evidence that many patients report better control of several cancer-related symptoms,” said Dr Dylan Zylla, oncologist and medical director of the HealthPartners Cancer Research Center.
The data also show that patients were using a wide variety of cannabis products rather than a single standardised medicine. Inhaled products, including flower and vapes, accounted for 48% of purchases, while orally consumed products such as capsules and gummies accounted for 42.5%. Products containing high proportions of tetrahydrocannabinol (THC) relative to cannabidiol (CBD) were common in both groups.
Around 15% of patients reported at least one side effect during the study period. Of the side effects recorded, 60% were classed as mild, 34% as moderate and 6.2% as severe.
Dry mouth was most frequently reported, followed by drowsiness or sedation, mental clouding and fatigue.
The findings add to a growing body of research examining cannabis as supportive care for people with cancer. In 2025, a large analysis of cannabis and cancer research found substantial support in the scientific literature for cannabinoids in managing treatment-related symptoms including nausea, appetite loss and pain.
