人可以喝海水嗎？
Seawater contains salt, so when people drink it, their cells take in both water and salt. Our bodies can safely handle small amounts of salt, but seawater contains far more salt than the human body can process.
When we eat salty food as part of our normal diet, we also drink liquids, which dilute the salt and keep it at a healthy level. Living cells do need sodium chloride, or salt, to keep the body's chemistry in balance. However, too much sodium can be deadly.
The problem is the kidneys. Human kidneys can only make urine that is less salty than seawater. So to get rid of all the extra salt from drinking seawater, you would have to pass more water than you drank. In the end, you would die of dehydration, even as you became thirstier and thirstier.
海水裡含有鹽，所以人喝海水時，身體的細胞會同時吸收水和鹽。人體能安全處理少量的鹽，但海水裡的鹽遠遠超過人體能夠處理的量。
我們平常吃鹹的食物時，也會喝水或其他飲料，把鹽稀釋，讓體內的鹽分維持在健康的程度。活細胞確實需要氯化鈉，也就是鹽，來維持身體的化學平衡。可是鈉太多的話，是會致命的。
問題出在腎臟。人的腎臟只能製造比海水淡的尿液。所以，要把喝海水攝取的多餘鹽分全部排掉，排出的水就得比喝進去的還多。到最後，人會越喝越渴，最後因為脫水而死。