While Halloween can offer some spooky but safe thrills to young trick-or-treaters, the haunting holiday can often be a stressful time for pets, the Humane Society of Canada is cautioning.

Michael O'Sullivan, the executive director of the Humane Society of Canada, warns that pets are often frightened by crowds of young children coming to the door. He also advises revellers to leave their pets at home.

"Don't keep pets outdoors during Halloween and ensure that they have a safe, quiet place inside where they aren't frightened by all of the noise and excitement and where they cannot escape through the constantly open door," O'Sullivan said in a news release.

"A quiet, inner room where they can't hear much of the noise from trick-or-treaters usually is effective. Putting a radio or television on in the room can also be effective."

Pet owners should also keep their pets away from decorations.

If people put the animals into costumes, they should make sure their pets are comfortable and can breathe and see properly.

Children should not share their treats with their pets given that chocolates and candies, which often contain the alkaloid theobromine, can be toxic to dogs.