Care will kill a cat.

The proverb treats worry as powerful enough to harm even a cat. Here, “care” means anxious preoccupation rather than kindness or responsible attention.

It warns that dwelling on a trouble can take a toll without helping to resolve it. The point is not to ignore problems, but to avoid letting concern consume you.

Use it to caution someone against repeatedly fretting over a problem when that worry is not helping them act. It can offer gentle reassurance, but may sound dismissive if the person needs sympathy or practical help.