Coconut water is the water found inside a young coconut. Coconut water is usually sterile and when mixed with plasma can act very much like saline. However, its sodium content isn’t high enough to stay in the bloodstream for very long.
Coconut water was reportedly given intravenously to people during World War II when regular IV saline solution was in short supply. But under normal circumstances, doctors today say while it might not be harmful, they wouldn’t be inclined to set up a coconut water IV for dehydrated patients.