What illnesses can it be a sign of? I know some, but want as much info as possible. A lady I know is having trouble with her cat who keeps weeing on her bed when she's in it. She's convinced it's not a medical problem, but if I can make her aware of how many possible health issues it could be, she might re-assess the situation. She loves her cats dearly and says this particular cat hasn't been the same behaviour wise since the loss of her husband just over a year ago.