I have 2 cats called Poppy and Daisy. We got back Friday before last from a 2 week holiday. My older brother was feeding them whilst I was away. When we came back, I noticed some sick in 2 places upstairs. Cleaned it up and thought nothing of it. However, came home on Friday to find that one of them had been sick on my bed. Not sure which one it was so just cleaned it up again. Then yesterday I had a kebab. I sometimes give them a little bit of the meat and they are always fine with it. Well I'm not doing this again, just in case because about an hour later, Poppy was sick but Daisy was fine. Then at about 4.30am this morning, I got woken up by the sound of Poppy trying to be sick. Nothing came up. Then when I got home from work this evening, I found that one of them had been sick again. Again, not sure which one this time as I wasn't there. This time, it had grass in it so I assume this is what made them sick. I went to the vets today just to get them their flea drops and some worming tablets and spoke to the nurse there. She said that if they continue to be sick after tomorrow then I need to bring them in in case they have a stomach bug. Has anyone had any experience of this? I've known my cats to be sick but not this often. I've changed their food since we came back from holiday so don't think it's this. I'm thinking it is Poppy that is being sick when I'm not around but obviously can't be sure. But her behaviour hasn't changed at all. Nor has Daisy's. They are both still playful and are both still eating so, if it weren't for them being sick, I would never know that anything is up. Do you think this is anything for me to worry about?