It’s not unusual for a cat to cough up a hairball. I have two cats and every now and then both of them will cough up a hairball.  Hairballs are not normally dangerous to cats but they could be misleading to cat owners because sometimes they mask other problems. When a cat coughs or vomits frequently people will tend to blame it on hairballs. There could be something more serious going on.  For example, a vomiting cat may have eaten something that it shouldn’t have like a button or coin. If you think that your cat has swallowed something unusual, don’t hesitate, take him to the vet right away for an x ray.  Your cat should also go in for a checkup if he is sick to his stomach more than once a week, is losing weight or is vomiting up food not just saliva or the occasional hairball. If it is just hairballs, there are pet medications that can control the problem.