Charcoal has saved my puppy from parvo, but I had another dog recently come down with parvo. He was much more sick than the first and would not even TAKE the charcoal chicken broth. He wouldn't eat wet food, wouldn't drink broth, and I couldn't force fluids down his throat. He seemed to be near death. What really kills dogs with parvo is dehydration. Knowing this, I went to a feed store and bought a large (10ml) syringe and needle. I then bought pure saline wound wash from Walgreens (MAKE SURE THERE ARE NO OTHER INGREDIENTS OTHER THAN SALINE). I then sucked the saline from a very clean bowl into the syringe and pumped it into his little neck 3- 4 times in the first 3 hours. In total, I put about 30ml of liquid into his scruff, not his muscle. More for a larger dog would be necessary. He was so near death that he didn't even fuss. The next day, he was so much better and ALIVE!! I knew he would have died if I hadn't pumped him full of saline. I continued with the saline inections, about 30-50 mls for the next two days until he started to complain. I also gave him charcoal as soon as he started eating and drinking. I also gave him some antibiotics in his food, the kind you get for fish at the feed store. I gave the antibiotics because I had them, but he was markedly better BEFORE I even started them due to the saline.
The whole thing cost about $30 including the gas to get around. It would have cost $300-$500 at the vet and the most effective thing the vet does is give your dog an IV of SALINE.