Many people with cancer want to use cannabis (marijuana) to ease side effects but don’t know where to begin, according to palliative care expert Brooke Worster, MD, FACP, at Sidney Kimmel Cancer Center at Thomas Jefferson University in Philadelphia. Her recommendations: 

Start with your oncologist. “You won’t get in trouble and won’t be judged, and it won’t interfere with your chemotherapy,” she says. If your oncologist professes not to know much, “Ask for a referral to a medical professional who has expertise in this area.” 

Know what it’s best for. If you have chemotherapy-induced nausea and vomiting, especially if prescription anti-emetics are not working well, adding cannabis is low-risk and often effective. There’s growing evidence that it works well for cancer pain too. “It may even supplant some pain meds,” says Worster. “For example, some people need less opioid medication.”  

Choose the right product. A product that combines non-narcotic CBD (cannabidiol) with euphoria-inducing THC (tetrahydrocannabinol) is often more effective than CBD alone. However, edibles and concentrates are easy to overdo, and smoking can impair lung health. Better choices include oils that can be vaporized (quick-acting for rapid relief) and tinctures (easy to take in small doses). For localized pain, consider topical creams and ointments.   

Start low, go slow. Don’t let the salesperson in a medical marijuana dispensary load you up. Taking too much, especially at first, can bring on dizziness (a fall risk), cognitive confusion and a racing heart. Best to start with a very small dose and slowly increase if needed. 

Educate yourself. “Every state with legal medical or even recreational marijuana has a website,” says Worster. “That’s a great place to start. It’s usually run by the state’s health department, so the information will have had medical oversight.”