My 10year old male indoor neutered cat vomits every night toward morning. It is yellowish tan-gold color with no food or hair in it and is pretty runny. He eats Friskies Ocean Fish wet in the mornings and Purina Sensitive Stomach Dry in the evenings. He rarely ever is able to sneak outside. I have had him to the vet and got no answers. There is some dry food left out at night if he wants to munch at night, but I have tried putting that away to see if it would help and it doesn't change anything. The vomiting does not coincide with any food, or other, changes. I haven't seen any other changes in his weight or behavior. I feel so bad for him and sure do not like waking up to messes every morning.