The toxicity or non-toxicity of a Christmas cactus depends on how you have grown your plant. ASPCA plant database shows that the Christmas cactus on its own is not poisonous to cats. But the chemicals and insecticides used on the plant could be toxic.
The Christmas cactus though classified as poisonous does not pose a threat to adults. However, though safe, no parts of the plant should be consumed. The sat that comes out of the leaf-like phylloclade can cause skin irritation.
We draw one conclusion from the argument is Christmas cactus poisonous to cats. This conclusion states that the Christmas cactus is not poisonous! What they do is cause digestion issues to your pet if it chews on it.