Frothy cat sick

[Toddlerteaplease]

Sorry
One of my cats has vomited clear frothy fluid 3 times over the last few weeks. No food or bike just clear. I am totally a helicopter cat parent but is it anything to worry about. Normal sick wouldn't bother me at all. She's fine in herself. Shiny coat and bright eyes. Eating and drinking and pooing well.

Ours does this. No idea why.

We've had this. Think this is when they've been eating grass. They do it to give the digestive system a bit of a clear out. Think - hope - it's normal and harmless!