Police now say there are two cases of dogs falling ill after eating something from the ground in an northwest London neighbourhood.

In late January, one-year-old Wriggley suffered seizures after eating what looked like stuffing from the ground in the Chesham Park area.

He has since made a full recovery, but Dr. Paul Francis, a veterinarian at Komoka-Kilworth Animal Clinic, says he could have died without fast action and remains concerned.

"I would say this is not accidental. I don't know how you would ever come up with the amount of this drug to make this dog as sick as it was."

The drug has now been identified as Dronabinol, a synthetic form of THC, the active ingredient in marijuana, used to restore the appetite of AIDS and chemotherapy patients.

France says only a limited number of people would have access to that particular drug.

"I spoke with the pharmacist at the Cancer Clinic in London here and asked about the drug - how frequently they're using it. And they said it's been discontinued in our area since about 2013 so some people have probably hoarded the drug for medical reasons."

And London police Const. Sandasha Bough says a second, similar incident has been reported in the same location.

"At this time we know that we have two separate cases where dogs have become ill after being in the Chesham Park area."

And police say their Facebook page has received a number of posts from people who also believe their pets may have been poisoned.

Now they're asking those people to call them to provide details.

"We're urging the public to come forward with any additional information," Bough says. "If your dog become ill, make sure that you go to the veterinarian right away and contact the London police so we can put the pieces together and see if these cases are linked in any way."

She adds that willfully causing harm to an animal can carry a penalty of up to five years in jail.