I also have had
chemo as I have lung cancer, I have 2 dogs that were not affected at all by my getting
chemo, why would you think it killed your cats and changed the behavior of the other cat, I do not understand what makes you think this, if your cats somehow got into a chemo drug it could definitely kill them but if you yourself alone had taken chemo and didn't have them drinking your urine somehow or taking in any bodily fluids I don't think the cats would die because of you taking ch