Some say love is the best medicine - in this case, we're talking puppy love.

A new study by the American Humane Association (AHA) is launching what advocates say is the first clinical trial of the effects of animal-assisted therapy (AAT) on young cancer patients and their families.

"Obviously, we know that the children like to see the dogs," Amy McCullough, AHA's national director of humane research and therapy, told NBC News. "But the folks in risk management want some clinical data."

Doctors say they've known about the value of pet therapy for years, but this study aims to provide factual evidence of what professionals have only guessed at.

Backed by a nearly $1 million grant from veterinary health firm Zoetis, and with the Pfizer Foundation's support, the Canines and Childhood Cancer Study hopes to find positive physical and psychological effects of animal therapy on the child patients, family members and caregivers.

"It's really this crucial exploration of the child-animal bond and how that is a crucial path to healing," added AHA president and chief executive Robin Ganzert.

Researchers designed a randomized, controlled trial in five children's hospitals where they will follow 100 children, ages 3 to 12, who were recently diagnosed with cancer. A lucky 50 kids will receive visits from trained therapy dogs, and 50 will receive standard treatment without the cute canines.

Over the next five years, the study will track blood pressure, heart rate and psychological responses in the kids, their families and the caregivers, McCullough said. It will also test the effect on the dogs, measuring the level of the stress hormone cortisol in the animals' saliva before and after visits.

These wonder dogs are not just ordinary pets either, noted Scott Baggett, a certifier for a large AAT agency called Pet Partners. They have to pass rigorous obedience tests and a thorough medical exam.

AHA just brought some of its furry friends to Washington, D.C. as a promotional event for its new study, USA Today reported.

The study's results are expected in 12-15 months.

"We are going to be able to put some data behind it and get people really enthused about the power of pets and the power of animals," AHA member John Payne declared.