My dog is throwing up this brown stuff. And I don't know what is it!! :( :mad:

I don't mean to be unkind. But, instead of spending precious time asking people here, how about taking your dog to the vet as soon as possible? No one here can examine your pet. Maybe there is something serious going on that needs immediate treatment by a veterinarian.

Some more details would help. Certainly if the dog is showing other symptoms, let us know. It is quite common for dogs to forage indigestible and throw up. I see no need to pay an arm and an leg for weekend vet care in most cases. The brown stuff could be some yummy feces it found somewhere. Withhold food for most of the day. Don't feed as long as it is still throwing up. If it isn't settled by tomorrow, call the vet.

Even when throwing up is due to a serious problem such as an intestinal blockage, usually there is no rush for treatment.