City officials are out with a warning about Woodbine Beach.
They're telling pet owners to keep their dogs leashed and close by, if they're out for a walk nearby.
It comes after city crews cleaned up about 30 dead ducks from the shore last weekend.
There's speculation from animal welfare advocates that bacteria that causes botulism contamination is to blame.
However, what killed the birds has not been confirmed.
Toronto Animal Services says some of the remains have been sent to the Canadian Wildlife Health Cooperative so that tests can be run to determine the cause of death.
Results could take about 2 weeks to come back.
Animal Services urges anyone who has recently visited Woodbine Beach with their dog, and notices their pet showing signs of sickness, to contact their veterinarian right away.
NEWSTALK 1010's resident veterinarian, Dr. Clayton Greenway, stresses that botulism is very rare, but says that its important you get your dog to a vet, if you see the symptoms.
Those can include weakness in the limbs, excessive salivating, and difficulty breathing.
Dr. Greenway says no matter what's behind the trouble at Woodbine Beach, this is a valuable reminder to dog owners to make sure that they're watching closely what their pets come into contact with.
"We have to remember that there are dangers on the ground and at the very least, if (your dog) ingests material like this, they can get an upset stomach," he says.
"Even that can send you into a veterinarian and cause you an expensive bill."
Woodbine Beach will remain open while authorities investigate.