Can weed help with cancer symptoms?

August 15, 2020
Cancer and Weed Help
Cancer and Weed Help

The two most common questions in terms of cannabis and cancer are in relation to whether cannabis can cure cancer and Can weed help with cancer symptoms.

You can read more about the question of cure here.

Cancer is a common and devastating disease being the second most common cause of death in men and women, both in the US and most of the developed world (only after heart disease which is first).

Symptoms of Cancer vs Symptoms of Treatment

It is important clinically to distinguish the use of cannabis for treating the symptoms caused by the physical and chemical presence and effects of the carcinogenic tumors themselves from the side-effects of the medical and chemotherapeutic treatments causing side-effects that are then subsequently treated with cannabis and/or specific cannabinoids. Already the use of cannabinoids in the treatment of cancer is well established with Marinol (Dronabinol) a man-made form of THC (Delta 9 THC) which since its approval in 1986 is used to treat the nausea and vomiting from chemotherapy – though it is also used to treat loss weight loss due to appetite suppression from the cancer or the treatments.

Most Common Uses of Cannabis in Cancer Treatment

1) Antiemetic Effect (nausea and vomiting)

For patients and their loved ones, nausea and vomiting remain one of the most distressing and common side effects of chemotherapy. Some agents have a close to 100% rate of causing nausea and it can be very severe indeed and reduce the quality of life significantly. However newer classes of medications such as Zofran and Ondansetron are very effective and work by blocking the 5HT receptors and so synthetic THC such as Dronabinol and Nabilone are less commonly used these days though some trials show that THC can be equally/more effective.

However it is also important to note that the man-made THC which has been approved by the FDA is the same as naturally occurring THC which therefore in itself shows the viability of cannabinoids as an effective medical therapy. The FDA is aware of the many clinical trials showing the effectiveness of THC in reducing chemotherapy induced emesis (vomiting).

Interestingly combining the results of multiple randomized studies have shown that amongst some populations of cancer patients the effectiveness of the man made THC was higher than many standard nausea treatments and certainly placebo.

Another  review concluded that patients treated with cannabinoids had significantly improved results vs placebo but unsurprisingly the side-effects such as dizziness, low blood pressure, anxiety and the psychoactive effects lead to a higher rate of patients stopping usage than placebo.

These trial were done with oral THC and so the results cannot be extrapolated to inhaled THC without reviewing the available data which is currently mixed. This is further complicated by the fact that newer standard medications for nausea and vomiting need to compared with not only THC but other cannabinoids such as Delta 8 THC (which is considered to be very good) and in combination with other cannabinoids such as THC:CBD.

It is also important to consider the potential for the entourage effect to increase or decrease the effectiveness of the cannabis. The entourage effect is the fact that as there are so many cannabinoids and terpenes etc in cannabis (vs isolated THC) and all of these can effect/enhance/detract from the function of the others at the receptor level – thereby making one strain of cannabis potentially good for cannabis while another may not be.

2) Appetite Stimulation

A reduction in appetite and weight loss with the associated wasting of cancer (called cachexia) are major problems for the quality of life and health of cancer patients. This is above and beyond the fact that nausea and vomiting themselves are a hindrance to not only adequate caloric and nutrient intake but can also be socially disruptive in that patients may not want to join others for meals for example.

Munchies and appetite stimulation are well known side-effects of smoking or using weed. But though small trials show that oral THC can increase appetite and weight gain other trials have shown lack of an effect for oral ingestion of THC – and unfortunately there are no studies for inhaled THC in cancer populations.

3) Pain control (Analgesia)

Pain is a major factor in the quality of life (QOL) of cancer patients and can be very severe and debilitating with metastasis causing bone pain through inflammatory or invasive mechanisms and can cause fractures and/or impinge on nerves and cause injury.

It is therefore imperative that pain management be central to a patients care. Whereas opiates are highly effective they are sometimes not well tolerated and many patients as such use marijuana to help control their pain and/or reduce their usage of other analgesics.

By acting at the CB1 and CB2 cannabinoid receptors in the CNS (central nervous system and brain) cannabinoids that are agonists to these receptors, turn them on by binding to them.

Two studies examined the effects of oral delta-9-THC on cancer pain. Using various doses varying from 10mg to 20mg they found “substantial analgesic effects” as well as reduction in nausea and appetite. In one study 10mg THC was equivalent to a 60mg dosage of codeine in reducing pain – and in fact many patients say that the use of cannabis can dramatically reduced their dependence on opiates within cancer patients (and others).

Yet other studies have demonstrated the efficacy of a THC:CBD extract in reducing pain. Three groups were assigned to either a  THC:CBD extract, THC extract alone, or placebo. The researchers concluded that the THC:CBD extract was helpful in managing pain and help sleep in advanced cancer patients whose pain was not fully controlled by opioids.

Animal models also support the potential for combining cannabinoids with opioids and studies have shown that combining them lead to a significant decrease in their pain.

4) Anxiety and Sleep

Anxiety and Sleep disorders are very common in the population and more so in cancer patients who have to deal with the disease, uncertainties, medical treatment and the side-effects they must deal with.

As such many cancer patients use cannabis to treat their anxiety and for sleep too.

Sleep can be disturbed not only by anxiety but also the pain and nausea we have discussed so cannabis may in fact effect the anxiety and sleep directly – or they may enhance sleep by for example reducing pain, allowing patients relief and the ability to fall asleep.


There are important and significant uses for cannabis and cannabinoids in treating the symptoms of the cancer or the potentially very side-effects of the treatments. Continued clinical research is required to measure the effectiveness of cannabis as treatment but there are plenty of reasons to believe that cannabis may improve quality of life in cancer patients by helping manage pain, nausea, appetite, anxiety and pain.

Further research is ongoing and it is important that cannabis and other treatments being considered are discussed with oncologists and other physicians.

More Information:

For more information about Clinical Research and Studies in the treatment of Cancer and Cancer Side Effects using Medical Marijuana, see below: