SAN FRANCISCO (AP) _ San Franciscans now have a new way to define their relationship with man's best friend. The San Francisco Board of Supervisors passed an ordinance Monday to change the city's health code to make pets owners also pet guardians.

The San Francisco Health and Human Services Committee urged the board last November to change the law so the city's pets will be considered animals and not personal property.

``We're really trying to get to the heart of trying to treat animals more humanely and promote guardianship,'' said Board of Supervisor president Matt Gonzalez, chief sponsor of the ordinance.

The board passed the ordinance 8-3. The new law needed only six votes to pass.

Supervisor Gavin Newsom said the proposal could cause confusion among pet owners and veterinarians. He also pointed out that the legal definition of ``owner'' and ``guardian'' is different and could open up the city to frivolous lawsuits.

Meanwhile, the Los Angeles Board of Animal Services Commissioners on Monday voted 2-1 to abandon efforts to use ``animal guardian'' in official city documents, rescinding a June 24 decision. Commissioners Helen Ann Johnson and Laura Beth Heison supported Monday's change. Commission president Paul Jolly opposed it.

Los Angeles area veterinarians, the city's Department of Animal Services and the City Attorney believed that dual definitions could confuse owners and regulatory agencies, thus reducing pet ownership and perhaps sparking frivolous lawsuits.

Laura Cavaluzzo, spokeswoman for San Francisco Dog Owners Group, an organization dedicated to expanding canine access areas in the community, said she had mixed feelings about the change and that the topic had sharply divided the group's members.

``People want to make sure guardian is not one step toward the slippery slope of doing away with pet ownership,'' she said. ``Others say guardianship is downright silly. They consider themselves owners and not guardians.''

San Francisco follows a list of other cities that have already changed their books to make ``pet guardian'' official. Boulder, Colo., was first to take action followed by Berkeley, West Hollywood and the state of Rhode Island.

San Francisco Mayor Willie Brown has 10 days to sign the ordinance into law. If he vetoes it will go back to the board one more time where it will need to pass with eight votes.

The board's decision might put to rest the debate among San Francisco's pet owners, but it has left the Cavaluzzo with one last question.

``We're the dog 'owners' group. What are we going to do with our letterhead?''