This is one of those recipes that everyone should know. It tastes terrible, but it works miracles. It is designed to keep people hydrated. It was created by Canadian researchers. UNICEF embraced it, and a commercial version is now distributed widely (mostly free of charge). Each year it is credited with saving the lives of at least a million children. I lived in the Middle East, Africa and Southeast Asia and it was a Godsend in all locations. A litre and a quart are about the same in size.
The ingredient list includes some options to make this taste better, but I have found that people who really need it, think it tastes okay as is. Don't use all the options -- just one.
Also, please don't review on taste -- review on results. Namely -- did the user not have to go to hospital to be rehydrated.