"People will be able to tell immediately that the dog is not well, and we urge them to get the animal to a vet as quickly as possible," said Allison Cooper of the Booysens SPCA.
A poisoned animal will start vomiting and losing control of its bowels and bladder.
Owners need to be careful not to come into contact with the vomit as it is poisonous.
According to SPCA guidelines, all the vomit should be collected in a bag or sealed container and taken to the vet.
Those who can't get the animal to help are urged to give the dog salt water to encourage vomiting.