Due to many cases of diseased cats and dogs at Veterinary clinics in Norway where poisoning with the mouse poison alpha-chloralose was a possible diagnosis, the Norwegian Veterinary Institute, with support from the Norwegian Environment Agency, initiated a collection of material from relevant cases. Cats and dogs that were clinically ill or dead with alpha-chloralose poisoning as a suspected cause were included in the project. The purpose was to get more information about alpha-chloralose poisoning in cats and dogs in Norway.

During the collection period, 37 cases were investigated; 4 dogs and 33 cats. The reason why most cases of poisoning were registered among cats is believed to be that they are more sensitive to this toxin than dogs, probably related to a reduced ability to excrete the substance in the kidneys. Cats eat mice to a greater extent than dogs, and it is likely that cats can be poisoned with alpha-chloralose by eating poisoned mice.

Poisoning with alpha-chloralose causes ataxia and disorientation, often with excitation. The animals get reduced body temperature and at higher doses, a state of anaesthesia occurs. The prognosis is good if the animals come home and receive supportive treatment. Usually they recover after 2-3 days. For animals that are not found in time and remain in a poisoned state outside in cold environments, the prognosis is characterised as poor.