Medical marijuana has been approved for human use in 22 states, but now there are talks of using the plant on sick pets.

Medical marijuana, commonly used to relieve chemotherapy nausea and pain, is now being used to help pets manage pain and chronic illnesses. Why use marijuana for animals? To put it simply, those who've experimented with the drug for their pets say it just works. And in states where it's legal, some companies are leading the way in marijuana- and hemp-based naturopathic medicine. 

Seattle-based Canna Companion uses ground-up hemp plants to make capsules, which don't contain delta-9 tetrahydrocannabinol, or THC, the more active ingredient in marijuana, according to CNBC. Instead, they contain cannabidiol (CBD), the ingredient most useful for treating pain and other medical problems. Another Seattle company, Canna-Pet, makes similar drugs. By omitting THC, and keeping CBD and many of the other 60 or so cannabinoids in the plant, pet patients can get pain relief without getting high. 

Nevertheless, these companies are going the safer route when it comes to medical marijuana for pets. Some veterinarians and medical marijuana patients are using the actual drug. 

Dr. Douglas Kramer, a Los Angeles veterinarian, is one such person, according to the Daily Mail. He tested out the plant on his dying dog Nikita after she had surgery to remove tumors. After ingesting the marijuana, Nikkita lived for six more weeks, and even showed signs of weight gain and less pain.

"Nikita was wasting away, and she’d stopped eating," Kramer told the Journal of the American Veterinary Medical Association in an article last year. "I’d exhausted every available pharmaceutical pain option, even steroids. At that point, it was a quality-of-life issue, and I felt like I’d try anything to ease her suffering."

California resident Ernest Misko also tried the drug while experiencing severe back pain. His results were so great that he decided to give his aging cat, Borzo, some — he was having difficulty walking. After just a few days of using the drug, Misko noted great improvements in Borzo, who was able to walk around a lot better, and appeared to be pain free. “I don’t get high from [marijuana], but the pain goes away. So I tried it on my cat, my 24-year-old cat, who’s feeling better,” Misko told the Journal.

Cannabinoid-based drugs have also been used for quite some time in the U.S. Nabilone is one such drug, which is also a synthetic cannabinoid. It's used as an antiemetic for nausea and vomiting and an analgesic (pain killer) for neuropathic pain. It is also used for treating everything from eating disorders to AIDS. Cannabis oils are also used to treat tumors.

For pet owners convinced that they should give their dogs or cats pot, it's important to be aware that even in medical marijuana-legal states, it's illegal for veterinarians to prescribe or even recommend marijuana to treat patients. Also, the side effects of marijuana are still unclear. Although it's natural, that doesn't mean that ingesting it will cause no harm.

A 2012 study from the Journal of Veterinary Emergency and Critical Care found that marijuana toxicosis cases had quadrupled over the course of five years in dogs, as the number of state medical marijuana registrations increased.  Two dogs mentioned in the study even died after ingesting marijuana-infused butter.  

Suggesting that pet owners proceed with caution, experts are interested in the possibility of using marijuana in veterinary practice. “My gut reaction is they do probably provide some therapeutic effect benefit," Dr. Dawn Boothe, director of the Clinical Pharmacology Laboratory at Auburn University’s College of Veterinary Medicine, told the Journal. "But, I'm never going to say there’s enough benefit that marijuana should be given to pets. I’m saying there’s enough justification that we need to study it."