Water makes up 80% of the human brain

While up to 60 percent of the human body is water, the brain is actually made up of an even higher percentage of water. The human brain is made up of 80 percent water, making it the second most water-based organ in the body, ahead of the heart at 73 percent water and behind the lungs at 83 percent water. The brain is also considered the most important organ in the human body, and water plays an important part in both the function and protection of it.