Medical cannabis advocates can be fanatical about their claims. And for good reason. THC and CBD have been shown to help battle inflammation and pain better than many prescription drugs. We also know that cannabis can help treat seizures and muscle spasms.

In recent years some of the more exuberant fans of the plant have taken to claiming that marijuana can help treat cancer. Well the science is still out on that one, but we do know that it can help treat a number of negative side effects associated with cancer treatment. That means that medical cannabis has a role to play in making cancer patients’ lives much more bearable. If you have a loved one who is facing a battle with cancer, here’s what you need to know about marijuana:

Treating Tummies

Anyone going through chemotherapy will tell you that one of the worst side effects of the treatment is nausea and vomiting. The degree to which these effects can hit the patient will depend on the type of cancer that they’re suffering from and the type of chemotherapy.

Using marijuana to treat this specific issue has been one of the most well known uses of cannabis as a medicine in the modern revival. Its use as a treatment for chemotherapy-related nausea was one of the most commonly cited by activists in the ’90s. Marijuana is believed to have antiemetic properties that quell nausea, control vomiting and even counter motion sickness. The mechanism behind these effects is still unknown, but it’s accepted enough that drug companies looked for a way in on the action. Lacking the ability to develop pharmaceuticals from a federally banned substance, scientists were actually pressed to create artificial cannabinoids dronabinol (Marinol and Syndros) and nabilone (Cesamet) to use in FDA-approved drugs.

Cannabis’ power to stir up the munchies is also well-known, and many chemo patients use it to help increase their devastated appetites.

According to Marijuana as Medicine? The Science Beyond the Controversy, Alison Mack and Janet Joy describe a study in which researchers compared THC to metoclopramide, an effective and widely-used antiemetic. Every participant in the study received a dose of cisplatin, a chemotherapy drug associated with emetic side effects. The patients were randomly given either THC or metoclopramide to treat the nausea. Seventy-three percent of the patients who received THC vomited at least twice following chemotherapy, compared with only 27 percent of the patients who received metoclopramide.

The authors cite numerous studies where THC is shown to help reduce vomiting, but not as much as other drugs available.

But unlike other drugs, cannabis can treat more than just nausea.

Treating Pain

Using THC and CBD to treat pain is now one of the leading reasons that patients reach for the bong. According to the New Mexico Department of Health, 35,394 medical cannabis patients are enrolled in the program with chronic pain as their qualifying condition. It’s the second largest group of cannabis patients behind those suffering from post-traumatic stress. In a 2015 study published in the Journal of the American Medical Association, several trials involving thousands of participants that showed that marijuana helped ease chronic pain resulting from multiple sclerosis. The study examined trials performed between 1948 and 2015.

A 2016 study published in the Journal of Pain found that patients who used cannabis specifically to relieve chronic pain related to cancer reported a 64 percent reduction in the use of opioids and other pain medications. And in a 2015 study from the Journal of Pain and Symptom Management, researchers discovered that of 113 cancer patients using medical cannabis to treat cancer-related pain surveyed the majority reported improvement in pain, general well-being, appetite and nausea.

Some chemo treatments can also cause peripheral neuropathy when damage is done to the peripheral nervous system. The condition can cause pain and tingling in the hands or feet of affected patients and can be the source of tremendous discomfort. It’s believed that THC’s analgesic properties can help treat these issues, but there is still lots of research needed before anyone can say for sure.

Treating Anxiety

Maybe the greatest boon that cannabis can deliver to the cancer patient is its ability to relieve stress and anxiety. Many patients who are going through cancer treatments will suffer bouts of depression and insomnia, and marijuana is well known for its ability to deliver attitude adjustments and restful nights.

When dealing with the day-to-day grind of doctors, hospital visits, calls from well-meaning and concerned loved ones, treatments and the disease itself, a quick hit off the bowl and the relaxing freedom of letting go for a few minutes can do wonders.

Radiotherapy and the Lungs

One big concern surrounding the use of cannabis to treat cancer symptoms, however, is that smoking it could pose problems for those who have gone through radiation treatments or chemotherapy. One of the reasons people get so excited about the possibility that cannabis can treat cancer is a 2014 study published in the International Journal of Cancer that found that smoking cannabis leaves tar in the lungs which should lead to an increased danger of developing lung cancer. But the same study also discovered no correlation between smoking cannabis and lung cancer, leading some to question if the cannabis was somehow negating its own deleterious effects.

The American Cancer Society has even noted that, “Scientists reported that THC and other cannabinoids such as CBD slow growth and/or cause death in certain types of cancer cells growing in lab dishes. Some animal studies also suggest certain cannabinoids may slow growth and reduce spread of some forms of cancer.”

Nevertheless, smoking during radiation therapy can multiply the risks of contracting lung cancer, so users might look to other means of consumption. Since edibles might be off the table due to nausea concerns, and recent evidence has shown that vaping cannabis oil can be more harmful than smoking cigarettes, dry herb vaping might be a good avenue to explore.