My dog was knocked over by a car, after having bleeding removed from chest cavity and spending the night on a drip, was allowed home with no broken bones but heavy bruising, but he has not eaten and refuses food and its now 7 days since accident. He is 18 months old and still a slender (almost skinny) puppy, (male collie), the vet says just give him time but how much time will it take he is losing all his weight.

When was the last time you spoke to your vet?
7 days is far too long to go without food. If your vet still insists to give more time, get a new vet.

The maximum any dog should/can go without food is 5 days.

I agree with Sariss, get another opinion.

What foods have you tried to feed him? Just his regular food or something a bit more appealing?

Is he drinking OK?

Try hot chicken broth over dry food or even plain chicken broth.

The dog is tramatized. He needs to be occupied and played with. Very short walks. Take him to his favorite park. Go for a car ride, if that's what he enjoys.

Find a Vet that will put him on an IV.

Make sure he is drinking.

Thanks for your info, I have taken him to see a different vet, his temp was 106( apparently dog should be 101, stops eating at aroung 104 and 107 could kill him) so they took him in for 2 days so far. They have take 1 litre of bloody fluid from his chest cavity, been put on IV and given anti bioticts, getting better now. Thanks.

Good to hear.