Just keep an eye on her to see if she continues to throw up. I think it becomes more common for older cats to occasionally throw up - for whatever reason, especially if in recent time they have been 'under the weather' in general. Feeby has done so a couple of times in the past month - not her norm over the years. Each time she did it was pretty quickly after eating and the food came back up indigested (did Sassy's?). The first time, I am not sure why; but, it could have been from going longer hours overnight without eating anything. I am thinking the second time - I fed her a piece of deli turkey - the food was either going bad or just didn't settle well since it wasn't her normal food. On the last occasion, she went right to her dry food bowl to 're-fill' her tummy and did not throw up again. She, too, didn't do any kind of build up to vomiting, it just came up as she was walking away. I hope Sassy doesn't have another bout of vomiting!!!