Allergies are usually something you would have before you let the cat sleep in your bed. I am actually very allergic (headaches, sneezing, watery eyes, etc.) to my cats, but I vacuum constantly and brush the kitties on a regular basis. My husband was allergic to cats before we got Jack and Ali...he now is not. I think it was just because he wasn't around cats a whole lot before, he does fine around them now. I don't think that a cat sleeping w/ you would cause you to have allergies...I could be wrong though.