I have a one year old female cat. She throws up sometimes. I know it is normal for cats to throw up the hair balls. But my cat throws up food, sometimes food and hair ball together. Is it normal? Other than that, she acts normal, does't look like sick at all. She does eats a lot. Since I have a four month old kitten, I always keep their bowl of food full. Do I have to take her to the vet? Thanks!