What is going on what elderly cat who has episodes in which she meows defecates urinates drools and then is fine?

Sounds like your cat is having a seizure. They can be caused by several things- one of them is Feline Epilepsy. Talk to your vet- there are medications that can help control this.
Sounds like your cat is having a seizure. They can be caused by several things- one of them is Feline Epilepsy. Talk to your vet- there are medications that can help control this.