I don't know if butter is dangerous for dogs. I know in Greenland they feed the sleddogs a packet of butter.. but these are hard working dogs which need every extra calorie they can get.

Perhaps she needs to vomit. You could try to let her outside so she can eat some grass...?

But obviously... Calling the vet for advice is probably the best advice I can give you.

I hope she feels better soon.

-Varga