I've always given my cats' milk and they have lived to sixteen and a half years, seventeen and a half years, and both died naturally of old age, and the latest is about thirteen to fourteen years old, and still going - she has it on one side of her food bowl - she has the choice to drink it or not, there is always fresh water there if she wants it and she don't seem to get an upset tummy or anything (touch wood). She may not want it all,though I don't give her much, she's a very little cat and a fussy mare at that! She will only eat one particular brand of catfood and we are right under her paw - and she terrifies one of the dogs unmercifully!