The American Society for the Prevention of Cruelty to Animals' Animal Poison Control Center is warning veterinarians, their staff, and pet owners that the xylitol—a sweetener found in some sugar-free chewing gums, candies, and other products can cause serious—possibly life-threatening problems for dogs.

Dogs ingesting large amounts of products sweetened with xylitol may have a sudden drop in blood sugar, resulting depression, loss of coordination, and seizures, according to Dr. Eric K. Dunayer, a consulting veterinarian in clinical toxicology for the poison control center. The center is most concerned about products in which xylitol is the primary ingredient.

"These signs can develop quite rapidly, at times less than 30 minutes after ingestion of the product," Dr. Dunayer said in a statement. "Therefore, it is important that pet owners seek veterinary treatment immediately."

Some data suggest a link between xylitol ingestion and liver failure in dogs, he said, though those data are insufficient to draw firm conclusions.

Dr. Dunayer published a case study on xylitol toxicosis in the April 2004 issue of the journal Veterinary and Human Toxicology.