Here is one recipe for a homemade rehydration solution

Glass 1--Apple, grape, or orange juice (240 ml)(1 cup)
--Honey or corn syrup (2.5 ml)(1/2 tsp)
--Table salt (pinch)

Glass 2--Clean Water (240 ml) (1 cup)
--Baking soda (1.25 ml) (1/4 tsp)

Alternate Glass 1 and Glass 2 until no longer thirsty.

This came from my pharmacotherapeutics course. The lecturer cautioned against
the use of sports drinks (pick your brand) because the sugar content may
cause hyperosmotic diarrhea, which means that water is pulled from the body
to dilute the sports drink, instead the fluid moving out of the digestive
tract. She also mentioned that the commercial rehydration solutions have a
very short shelf life and the expiration date should be noted.

Becky Engel, RN, IBCLC
Athens, GA