Chlorine dioxide is extremely volatile. It doesn't last long at all. It is possible that it helps topically but inside the body it quickly reacts with the various biofilms in the body (mucous) and gets used up. Some of the chlorine dioxide reacts all the way down to salt but some only gives up one electron and ends up as chlorite.
It is generally believed that chlorite is what is helping inside the body.
Unactivated sodium chlorite started being used in the mid 1960's. At that time it was believed that the activation inside the stomach would oxygenate the body and that any improvements were from the additional oxygen. Unfortunately the results were not consistent and people can't tolerate higher doses.
Jim Humble discovered that if you activate sodium chlorite it has a chance of making it through the stomach and becoming available to the body. He got off on a tangent chasing chlorine dioxide but I expect eventually he will re-discover chlorite.
The key to using chlorite is in the activation. You want to activate it enough to be able to pass through the stomach with minimal additional activation but don't want to waste a lot of the sodium chlorite in producing free chlorine dioxide.
We have had wonderful success by using a pH meter to guide the activation. We are mixing up a gallon at a time and use distilled water. The target amount of sodium chlorite is added to the gallon of water, then an acid is added until the pH of the whole solution is reduced to about 5. At this point a small amount of salt is added to the mixture and it is left to activate for the next 24 - 48 hours at room temperature. 24 hours is OK for oral use but we go a minimum of 48 hours for IV use.
Since very little free chlorine dioxide is produced there are no issues with taste or odor and since very little additional activation takes place inside the stomach there are minimal issues with nausea and diarrhea.
Chlorite inside the body has the potential to deplete the body of essential minerals and hormones. It doesn't matter how the chlorite gets into the body.
The official ALS results from the clinical trail showed that about 42% of the people showed some measurable improvement. The unofficial results indicated that a lot more than that saw some benefits. Chlorite wasn't able to totally stop the progression of ALS and many who participated in the clinical trial has since died.
There is hope that chlorite along with a specific diet designed to rebuild the body may do better.