Interesting Facts: #19

The liquid inside young coconuts can be used as a substitute for blood plasma.

From The Straight Dope:

Coconut water can be used for a variety of medical purposes, one of which is intravenous rehydration. A 2000 report tells of a stroke patient in the Solomon Islands who was too ill to drink or use a nasal tube but was successfully rehydrated with a coconut-water IV when no other fluids were available. Emergency coconut IVs were reportedly used by the British and Japanese during World War II, and they've been clinically tested on humans several times to see how well they'd be tolerated. Answer: overall, pretty well.

Remember, we're talking about coconut water, the liquid found inside a young coconut, not coconut milk, which is made from grated coconut meat. Coconut water can't actually replace blood plasma; chemical analysis indicates it's closer in makeup to intracellular fluid. It's usually sterile, and when mixed with plasma it behaves like saline solution. It's got fewer electrolytes in it than our bodies are used to and too much potassium, so it's not an ideal rehydration fluid. But it works in a pinch.

http://www.straightdope.com/columns/read/2925/can-coconut-juice-be-used-as-blood-plasma-plus