Cannabis for Cancer: What Does the Research Really Show?

“Cannabis against cancer” sounds like a bold claim at first. At the same time, scientists have in fact been studying THC, CBD, and other cannabinoids for many years, as well as the question of whether they can influence certain processes in cancer cells. For me, however, this topic isn’t just scientifically interesting. Researching and thoroughly examining this topic is a matter very close to my heart. My goal is to help cancer patients and their loved ones—because they, too, suffer immensely from this situation. I want to help by presenting the facts clearly and, at the same time, by not giving up hope that there might, after all, be a way to combat this unspeakably terrible disease.

Why Cannabis and Cancer Have Been on My Mind for Years

Five years ago, I lost my mother to cancer. She was only 61 years old. Since my mother had to live with cancer for about 25 years, I witnessed firsthand what this disease can do to a person and their family. Medical tests, chemotherapy, immunotherapy, side effects, hope for the next test results—and then, after a few years, back to square one. Unfortunately, many family members know this situation all too well, and I deeply empathize with everyone out there who is personally affected or has a family member going through this.

At some point during her treatment, it was no longer just about fighting the cancer. It was also about everyday things: Can she eat anything? Can she sleep? How do you get that unpleasant chemical taste out of your mouth after chemotherapy? Right up until her deathbed, I instinctively kept offering my mother a joint. She refused it until the very end. Back then, I didn’t even know the exact scientific findings yet. But I was certain that the joint could help her—at least morally, emotionally, and maybe just by sharing a little humor together. I wasn’t concerned with a cure, but simply with improving her quality of life during this difficult time.

That is my personal experience. Today we know that medical cannabis is, in fact, used in Switzerland to treat, among other things, nausea and loss of appetite associated with chemotherapy, as well as certain chronic pain conditions.

An SRF report, new studies, and a special book, *Cannabis Against Cancer*

There are several reasons why this topic has come back to the forefront of my mind. For one thing, I recently came across a TV segment on SRF (Swiss Radio and Television) that revisited the topic of medical cannabis and cancer treatment. For another, there are constantly new, highly exciting study findings being published.

But above all, it’s due to a book that we carry in our own catalog. In 2017, physician and cannabis researcher Franjo Grotenhermen published the scholarly book *Cannabis Against Cancer: The State of Science and Practical Implications for Therapy* with the Swiss publisher Nachtschatten Verlag. Almost ten years have passed since its publication. What has become of these research approaches?

Voices from Oncology: DKFZ, ZIO, and Clinical Practice

Publications by renowned institutions show that this topic has long since been recognized by conventional medicine. The German Cancer Information Service (DKFZ) clearly emphasizes, however, that there is no scientific evidence that cannabinoids halt tumor growth in patients with advanced cancer. At the same time, a report by Georg Thieme Verlag notes that between 2015 and 2017 alone, approximately 3,000 cancer patients were treated with cannabis, primarily because it can alleviate many accompanying symptoms.

The Center for Integrative Oncology (ZIO) in Switzerland also confirms that cannabinoids are now used in many areas of medicine. They are specifically used as a complementary treatment during and after cancer therapy to support the quality of life of those affected.

The Endocannabinoid System: How Cannabis Actually Works in the Body

To understand why scientists are studying cannabis in relation to cancer, we need to take a look at biology. Every person has what is known as the endocannabinoid system (ECS). This complex network of receptors (primarily CB1 and CB2) is distributed throughout the body—in the brain, the nervous system, various organs, and the immune system. The ECS regulates basic functions such as pain perception, sleep, appetite, and immune responses. Since the active compounds in the cannabis plant (phytocannabinoids) are extremely similar to our body’s own neurotransmitters, they can bind to these receptors. It is precisely this mechanism that explains why cannabis can alleviate symptoms such as nausea or pain and why researchers are investigating whether these receptors also play a role in tumor cell division.

CBG and Rare Cannabinoids: A Focus on Inflammation and the Tumor Microenvironment

How Cannabinoids Attack Cancer Cells in the Lab: The 3 Mechanisms

In preclinical studies—that is, experiments involving cancer cells or animal models—researchers primarily observe three biological processes:

• 1. Apoptosis (programmed cell death): Cancer cells divide incessantly and ignore the body’s signal to die. In laboratory experiments, cannabinoids can trigger a cellular stress response that leads to an accumulation of the signaling molecule ceramide. This molecule forces the cancer cell to self-destruct, while healthy cells remained largely unaffected in the experiments.
• 2. Anti-angiogenesis (starving the tumor): For a tumor to grow, it needs blood vessels to supply it with oxygen and nutrients. Laboratory studies show that cannabinoids can block the release of growth factors such as VEGF, thereby inhibiting the formation of new blood vessels.
• 3. Inhibition of metastasis: For cancer to spread, cells must migrate. In cell models, it has been demonstrated that CBD downregulates genes (such as Id-1) that play a key role in cell migration and metastasis.

A systematic meta-analysis published in 2026 evaluated 189 preclinical studies and confirmed these antitumor effects across various types of cancer.

Why a Petri dish is not yet a cancer treatment

Herein lies the crucial point: If hemp extracts inhibit the growth of cancer cells under laboratory conditions, this indicates a biological mechanism. However, the human body is far more complex. An active ingredient must reach the tumor in the exact concentration required without first being broken down by the liver or causing serious interactions. In 2024, the American Society of Clinical Oncology (ASCO) published its first comprehensive guidelines on cannabis and cancer. The recommendation is clear: Cannabis and cannabinoids should not currently be used in place of cancer treatment.

Important for those affected: Be aware of possible interactions

When it comes to honest, expert advice, we must not gloss over potential risks. Immunotherapies are increasingly being used in modern oncology. Initial data suggest that high-dose cannabis could suppress the immune system and thus reduce the effectiveness of these specific therapies. In addition, cannabinoids such as CBD can block certain enzymes (cytochrome P450) in the liver that are also responsible for breaking down many chemotherapy drugs. If these drugs are not broken down quickly enough, they can accumulate in the blood. Anyone who wishes to use cannabis during cancer treatment should therefore always discuss this openly with their oncology care team.

Particularly interesting: Cannabis and Cancer, Including Glioblastoma

One of the most interesting areas of clinical research involves aggressive brain tumors (glioblastomas). In 2021, a small Phase 1b trial investigated nabiximols (a medication containing THC and CBD) in addition to the standard cancer drug temozolomide. There was a striking difference in one-year survival rates: 83 percent in the cannabis group compared to 44 percent in the placebo group.

ARISTOCRAT: The Next Level of Research

That sounds spectacular, but with only 21 participants, the group was too small to demonstrate a definitive survival benefit. That is precisely what is now being investigated in the British ARISTOCRAT study. This study is recruiting patients with recurrent glioblastoma through September 2026 and is specifically examining overall survival.

Cannabis and Cancer: Treating the Tumor or the Symptoms?

High-quality hemp products for well-being and quality of life

Precisely because we at Herba di Berna operate both a Swiss CBD online store and a CBD shop in Bern and offer a wide range of products, transparency is very important to us. The cannabis-based medicines studied in clinical trials contain strictly controlled amounts of active ingredients and are closely monitored by doctors to treat specific diseases.

Our product line is designed for people who want to naturally support their overall well-being in their daily lives. Whether customers purchase our standard CBD oil, prefer classic, gently dried CBD flowers for a relaxing evening, use nourishing hemp cosmetics, or buy practical hemp accessories, the focus is always on personal balance and relaxation.

Conclusion: Cannabis for Cancer—Neither a Miracle Cure Nor a Settled Matter in Research

Nine years after the publication of *Cannabis Against Cancer*, we now know more about the cellular mechanisms thanks to CBG research, meta-analyses, and studies such as ARISTOCRAT. Nevertheless, there is still no scientific evidence to support cannabis as a standalone cancer treatment. I will continue to follow the research closely. Because I know how great people’s hopes can be. That is precisely why this topic deserves both: openness to new scientific approaches and absolute honesty about what we know today.

References on the Topic of Cannabis for Cancer Treatment