Vidi ove mere, to je ORS za dijareju, mislim da to može i u čaj ako je neki jako blagi i biljni, a ne baš crni čaj:

Give the child a drink made with 6 level teaspoons of sugar and 1/2 level teaspoon of salt dissolved in 1 litre of clean water. Be very careful to mix the correct amounts. Too much sugar can make the diarrhoea worse. Too much salt can be extremely harmful to the child. Making the mixture a little too diluted (with more than 1 litre of clean water) is not harmful.

https://rehydrate.org/solutions/homemade.htm