Taking pets to work helps some people relax. But others see the animals as a distraction.

Hill's Pet Nutrition Inc. is a company that walks the talk -- and the dog too. At the company's site in Hertfordshire, Britain, several dogs can often be found in the office.

"We are a company of pet lovers. It is encouraged by the business and enshrined in the mission statement," says Libby Sheridan, veterinary affairs manager.

As Hills is a maker of pet products, this might be expected. But the Los Angeles-based advertising agency TBWA\Chiat\Day takes a similarly pro-canine line. There might be 40 to 50 dogs -- compared with 850 people -- in the company's largest office at any time, says Jeremy Miller, director of public relations.

"It has been going since 1998. It started with the company's chairman and chief officer, who's a dog lover. It creates a good environment." The only downside, he says, is "the occasional scuffle."

For many, the presence of the family pet at work is seen as a big perk, making them more relaxed and keeping them in good spirits. They may even work longer hours if they know the dog is under the desk.

The Blue Cross, an animal welfare charity in Britain, would like to see more canine companions in the office and has been running Take Your Dog to Work Day in Britain for the last 12 years. This year it will be Sept. 14.

"If it is practical it can be a great benefit," says spokeswoman Ziela Haider. "Dogs really do reduce stress. We have a part-time office dog and spending a few minutes stroking him lets you take a mental break."

Yet for a nation of celebrated animal lovers, British workplaces that cater to pet-owning workers are a surprising rarity. The nation that has truly embraced pets at work is the U.S. According to a survey by the American Pet Products Manufacturers Assn., nearly one in five companies allows pets in the workplace. In fact, employees are so concerned about their furry friends that last year American job website Simplyhired.com designed a filter to let candidates search for vacancies in companies that are pet-friendly; it is now one of the most popular.

There have to be rules for those who want to let the dogs in. The animals must be well behaved (with appropriate sanctions if they are not); they should not affect employees who do not like or get on with pets; the policy needs agreement by consensus; and there must be iron-clad rules about cleaning up.

Some are in two minds about the idea. Cary Cooper, professor of organizational psychology and health at Lancaster University management school in Britain, says inviting pets into the workplace could reduce stress, act as a perk and make the company a more fun place. But, on the other hand, poorly behaved or too many animals could cause workplace angst.

Still, he allows, pets definitely humanize colleagues: "People step out of the corporate roles they play with animals. You no longer think 'Fred's my manager,' you think 'Fred loves his dog.' "

Others are less equivocal. Stephen Welch, associate director at the Hay Group, a human resources consultancy, is concerned about the possibility for distraction, allergies and legal liability. "You could make a work-life balance argument for it, but businesses are places of work -- they are not a zoo and they are not show-and-tell. If you want to do better on work-life balance, let your employees do more work from home, so they can be with their pets."

The pets-at-work debate almost always revolves around dogs. It might be possible to have an office cat, but having employees bring their cats to work would lead to a lot of lost cats.