My cat is long haired and occassionally vomits hairballs. She does like to eat plastic, so I keep all bags and stuff away from her. Sometimes I find that she vomits after I give her too much cat treats. However, a while ago I was alarmed to see her drop to the floor on her side after she threw up. She got up and acted fine and for weeks now has seemed perfectly happy and healthy. Until tonight, she did the same thing. When she was vomiting, she seemed to be wretching badly, seemed like it was taking her awhile to vommit, so it didn't seem like enough oxygen was getting through, and she fell over on her side again. But then has been acting fine and healthy again. Should I be concerned?