Study review: Combination therapy with cannabidiol and chemotherapeutics in canine urothelial carcinoma cells

Date: 05 August 2021
Publication: PLOS ONE
Authors: Inkol JM, Hocker SE, Mutsaers AJ
Using: In-vitro lab study on canine cancer cells
Full study:


Bladder cancer is a deadly disease in dogs. With chemotherapy often proving unsuccessful, most dogs diagnosed with bladder cancer will die within a year.

Studies on humans with other types of cancer have suggested that CBD “induced apoptosis, reduced cell migration, and acted as a chemotherapy sensitizer in various human tumor types.”

So, researchers wanted to know – does CBD have any positive effect on bladder cancer in dogs? To find out, they exposed canine urothelial carcinoma cells to CBD in a lab test.

This was an in-vitro study, so there’s no guarantee that its results can be replicated in real life. However, the researchers found that “cannabidiol reduced cell viability and induced apoptosis in canine urothelial cells,” and significantly improved the effects of “mitoxantrone and vinblastine chemotherapy.”

Apoptosis is the medical term for programmed cell death. It’s the body’s mechanism for triggering abnormal cells to destroy themselves, which is blocked by cancerous cells.

Cell viability is a medical term for the health of cells.


This study focused on “canine urothelial carcinoma (UC), also known as transitional cell carcinoma,” which is the most common type of bladder cancer in dogs.

In dogs, bladder cancer is often lethal, as it’s hard to detect and treat. With surgery rarely an option, dogs with bladder cancer are given chemotherapy and other drugs, but the treatment has a poor track record, with variable effectiveness, “ranging from 0–58%.”

Even when chemotherapy is effective for dogs, they are only predicted to live a median average of “242 days from the start of drug treatment.”

So, with bladder cancer being so common, deadly, and hard to treat, researchers chose this disease to test out CBD’s reported anti-cancer effects on dogs.

“In human oncology studies, CBD has been shown to induce tumor cell apoptosis” – that’s the end-of-life mechanism of cells, which is initiated by the body when it detects an abnormal cell. In tumors, apoptosis is blocked.

The study tested the effects combined with the common anti-cancer drugs Vinblastine, Carboplatin, Piroxicam, and Mitoxantrone.

CBD used

The CBD applied to canine cancer cells in this study was made by MediPharm Labs. The study doesn’t mention if the CBD was a full-spectrum extract. See our recommended CBD oils for dogs with cancer here for more product-specific information.


The researchers conclude that, when applied to dog cancer cells in the lab, CBD can help treat cancer.

“CBD treatment reduced viability and induced cell death in canine urothelial carcinoma cells in vitro.”

CBD for dogs also seems to work well in combination with the chemotherapy drugs mitoxantrone and vinblastine. The researchers noted that CBD enhances chemotherapy “in a synergistic manner.”

These are exciting results! But it’s important to remember that there’s no guarantee researchers will see the same results when they test out CBD’s anti-cancer powers in real-life dogs.