When your cat has ceasures?

We have a 2 year old Siamese cat that has wierd spouts where she starts to foam at the mouth and breaks into something that resembles a ceasure. I started to pay attention to when they happen for chemicals, like after I cleaned or something...that wasn't it. They come and go, the last one was 8 months ago until last night. We are going to take her to the the vet and of course they will run tests, but was hoping that someone has gone through this before and could offer some insight. Thanks!!!