Coconut water has long been served as a refreshing beverage in many countries in South America and Southeast Asia and it is also gaining acceptance in the US. This water tastes good, it is loaded with nutrition and it is natural. It also contains few calories and contains essential minerals that help with dehydration due to exercise or other reasons. Coconut juice is rich in potassium, a mineral that is needed for optimal heart function and normal blood pressure. This water also contains magnesium and calcium and not fat and no cholesterol. It also contains little sodium. Its natural occurring sugars, 14 gr per serving, are a fraction of most soft drinks.
In the 1940's coconut water was given intravenously (American Journal of Diseases in Children and The American Journal of Emergency Medicine) to treat dehydration.
Coconut water is different from coconut milk which is a thick, cream-like liquid commonly used in Thai food cooking. Coconut water is obtained from young green coconuts and most of the supply come from Brazil.
Source: "Coconut Water for Health and Healing" by Bruce Fife, ND