Ice cream — Food safety facts
Feed with care · Dogs · full breakdown on the linked food page
Lactose, sugar and fat — most pets get diarrhoea. Check for xylitol and chocolate, which are toxic.
Short answer
Yes, a small lick of plain ice cream is generally safe for most dogs, but it should be given only as an occasional treat. Most dogs tolerate the lactose, sugar and fat, though many will develop loose stools. Be sure the ice cream contains no xylitol or chocolate, which are toxic. Watch for vomiting or diarrhea and call your vet if those signs appear.