Joe Tippens was diagnosed with late-stage lung cancer in 2016. He was told there was no cure, and he had only three months to live. The Edmond, Oklahoma man refused to give up. He combed the internet, searching for approaches outside of conventional medicine. He tried the spice curcumin, CBD oil, mega doses of vitamin E and—finally—something that has doctors scratching their heads. He took something you might use to treat your dog for worms. It worked.

The remedy: fenbendazole, which is FDA-approved to rid animals of intestinal parasites and can be purchased online for just a few dollars. A growing number of anecdotal stories suggest that fenbendazole can also treat certain cancers in humans. It is available by prescription, but many patients are taking it independently, using the drug in conjunction with other treatments such as chemotherapy and radiation to treat their own cancers.

Despite the anecdotal evidence, fenbendazole is not considered a viable cancer treatment by most medical professionals. It has not been extensively tested in human cancer patients, and its toxicity and side effects are unknown. In addition, fenbendazole may interfere with other treatments for some cancers. However, some people are having amazing results with fenbendazole, which has doctors and other health professionals scrambling to understand its role in the treatment of some types of cancer.

One theory is that fenbendazole works by blocking enzymes needed for cell growth, which allows normal cells to survive and thrive while killing cancerous cells. It may also stimulate the immune system and kill cancerous cells by targeting them and triggering their destruction. Scientists are studying fenbendazole and other benzimidazole anthelmintics—including popular dog dewormers such as pyrantel permeate and albendazole—as possible anticancer drugs.

Some of the most promising developments are in the field of targeted cancer therapy. This approach seeks to identify proteins or other substances unique to cancerous cells, then develop treatments that will target those molecules without harming healthy ones.

The best way to treat your pet’s cancer is to be proactive and take action as soon as you notice symptoms. Often, cancers are more manageable in their early stages when they are smaller and easier to treat. Keep an eye out for these common dog cancer symptoms and contact your veterinarian if you witness any of them: dog dewormer cancer