I recently had a tooth removed that became infected. Instead of having to go to the dentist and go through a whole anti-biotics cycle my grandma gave me a bottle of this silver stuff. I'm not one to fall for the whole snake oil medicine stuff but I figured i'd at least give it a shot. After a few uses I could tell that the swelling was going down and the stuff was actually working. After a few days the infection was gone and I was more than impressed with how well this stuff really works. I will say that I was using the more potent 2000 ppm stuff so I can't say if the 500 would work slower or not. I went ahead and bought a bottle off their website just in case. Totally worth it.