FORT COLLINS — Edward, a 4-year-old retriever, has had a bad hip since he was 6 months old.

In search of some relief, Edward's owner, Krystal Reagan, enrolled the retriever in a clinical trial at Colorado State University's College of Veterinary Medicine and Biosciences.

So, Edward has spent the past five weeks helping to answer the question: Can juniper, goldenrod, dandelion, meadow sweet, willow bark and cranberry heal an aching canine?

"Research has indicated that herbal supplements may be beneficial to humans, but that really doesn't tell us anything about dogs," said Narda Robinson, the leader of the research team.

Still, the marketing of herbal supplements for pets is exploding. "There are a lot of people making money without any proof these products work," Robinson said.

Not only may the products not work, she said, there is a risk they could cause gastric ulcers, kidney and liver damage, and diarrhea.

"Work like CSU's is necessary," said Susan Wynn, a veterinarian and nutritionist with Georgia Veterinary Specialists and an expert in alternative treatments.

"We need to know what works, why and at what dosages," she said.

The use of other "complementary" treatments, such as acupuncture, chiro practics and swimming, also is on the rise.

"Does swimming help a dog? We don't know. We are trying to put some numbers to these things," said CSU orthopedics researcher Kevin Haussler.

The herbal combination being tested is marketed by RZN Nutriceuticals Inc., which is paying for the $72,000 study.

"We have complete scientific independence, and whatever the findings, we are going to publish them," Robinson said.

That's fine with RZN, company executives say.

"Clinical trials on actual products have been lacking. That's why you get claims that can't be backed up," said Mark Lubin, RZN's chief executive.

The company has financed trials on its products for humans and horses. "You want every clinical trial to build on the last one," Lubin said.

So after horses and humans, dogs are getting their turn. Edward is one of 36 dogs participating in the trial, with half getting the herbal dose and the rest a placebo.

Once during each of five weeks, Edward has visited the CSU vet teaching hospital for tests.

Reagan and researchers said Edward's favorite test was the run down a chute over a set of pressure plates.

The plates measure the pressure that the dog places on each paw. A subject favoring a hind leg due to soreness, for example, will place less pressure on that limb. If the pain is lessened, the weight becomes more evenly distributed.

At the end of each run, Edward snapped into sitting position ready for the expected treat.

Getting the necessary reading requires the dog to hit each plate with one front paw and one back paw.

Some dogs have needed as many as 40 runs to get it right, Robinson said. That's quite a workout for the researcher and quite a load of treats for the dog.

The trots through the chute are videotaped so the images can be computer-analyzed for elements such as gait and hip motion.

It will be months before the trials are completed and the data refined, Robinson said.

And what of Edward? Is he feeling any better? "It's hard to tell. He's such a happy dog," Reagan said.

But last week, Edward, who has always struggled to get into the car, jumped into the back seat. "Now that was a surprise," Reagan said.

Mark Jaffe: 303-954-1912 or mjaffe@...