In less than 10 years, Joe and Judy Roetheli went from owners of a dog with bad breath to creators of the top-selling dog treat in America.

But dog lovers giveth and, on the Internet at least, sometimes they taketh away.

In the past few months, chatter about Greenies dog treats -- and their potentially deadly consequences -- has spread furiously throughout the Web. But, according to many dog experts, the toothbrush-shaped treats pose no more of a danger than any other edibles that don't dissolve in water, including rawhide and pig's ears.

Greenies are compressed chew treats that promise to help clean a dog's teeth and freshen its breath. The treats were developed by the Roethelis to help combat the bad breath of their Samoyed, Ivan.

The treats were the first ones certified by the Veterinary Oral Health Council, and last year overtook Milk Bone to become the top-selling U.S. dog treat, according to a study by Euromonitor International.

But these days, many users of message boards on Web sites like Dogster.com describe the treats as "dangerous" and "unhealthy."

Anecdotal information from veterinarians and dog owners is clear: there are dogs who have died after ingesting Greenies.

Whether Greenies are any more or less dangerous than anything else dogs ingest is less clear. With the hundreds of millions of the treats in circulation, are some dogs just bound to have freak accidents while eating them? Or are the treats inherently prone to cause digestion problems?

Michael Schaer, a professor of veterinary medicine at the University of Florida College of Veterinary Medicine, said he operated on a Lhasa Apso with a Greenie stuck in its esophagus just last week. After thousands of dollars in medical bills, the dog died of aspiration pneumonia.

Even though he's seen similar problems with Greenies "several" times, Dr. Schaer said he regularly feeds the treats to his own golden retriever.

The danger with Greenies, said Dr. Schaer, is that dogs will not chew the treats sufficiently, leaving open the possibility that they might get stuck in a dog's esophagus.

"If they don't chew them very, very thoroughly, that's when they get into trouble," he said. "It forms a bolus of foreign body material that just sits there like a boulder."

But Dr. Schaer stressed that Greenies are no more dangerous than rawhide or pig's ears. "I don't want to implicate Greenies as being public enemy number one," he said. "It's a brilliant product."

That's not the view of Jennifer Reiff and Michael Eastwood, a married couple in Manhattan. Their dog, a miniature dachshund named Burt, died this July after complications from the surgical removal of a Greenie blocking his intestine.

"There shouldn't be any problems once it was chewed sufficiently and swallowed, yet it blocked his intestine and he died 48 hours later," said Mr. Eastwood. "He was throwing up blood, vomiting blood and breathing blood bubbles -- it was the most horrible thing."

Mr. Eastwood is suing S&M NuTec, the company that manufactures Greenies, for $5 million in punitive damages. He said he decided to sue after the company offered him a settlement of about $8,500 ($6,500 for veterinary bills and $2,000 for the cost of a new dog), on the condition that he would not discuss his dog's death.

"There was no admission of any fault on their end," he said. "We weren't interested in getting our money back. We were interested in getting the product recalled."

Each bag of Greenies includes a warning: "As with any edible product, monitor your dog to ensure the treat is adequately chewed. Gulping any item can be harmful or even fatal to a dog."

In response to inquiries about deaths from Greenies, the company released a statement reiterating that its treats should not be fed to "dogs less than 6 months old, dogs less than five pounds, and dogs who gulp food and treats."

The statement also said that "Though injurious incidents with our product are rare, more often than not, the pet is not fed according to our feeding directions."

In his lawsuit, Mr. Eastwood asserts that approximately 60 to 80 dogs have died from Greenies. An investigation by Seattle TV station KIRO-TV found nine people in that area who said that their dogs had died after eating Greenies, or other dog treats modeled after Greenies.

But none of the four veterinarians in the Pittsburgh area interviewed for this story said that they had ever seen a dog that developed problems after eating a Greenie.

Sherwood Johnson, a veterinarian with Pittsburgh Veterinary Specialists in Shaler, often has dogs referred to him with esophageal or intestinal blockages.

He said that rawhide and chicken bones are the most frequent culprits for internal blockages. He's also removed a bottlecap, a bolt with the washer still attached, socks, underwear, gloves and even an entire bathroom rug from the insides of various dogs over his 11 years doing endoscopies.

But never a Greenie -- which he regularly feeds his own dog.

Regardless of whether it's a Greenie or any other dog treat, Dr. Schaer said that pet owners should monitor their dogs carefully while they eat, particularly if their dog starts to gag, salivate or act restless afterwards.

"This is something that occurs with enough frequency that everyone should be careful," he said. "Anytime any dog starts to look even a little bit abnormal after eating one of those things, seek emergency veterinary assistance. Do not wait."