"Water water everywhere, not any drop to drink.”
Ocean water is not suitable for humans because it is saline and if we intake salt in that amount then we will create a toxic concentration of salts in the body and as a result of this, your body fails eventually when it has to try to get rid of the salt that comes from seawater. Your body normally gets rid of excess salt by having the kidneys produce urine which carries the excess salt, but it needs freshwater to dilute the salt in your body for the kidneys to work properly. Tissue in your body also contains freshwater that can be used. But if there is too much salt in the body, your kidneys cannot get enough fresh water to dilute the salt and your body will fail. This can lead to potentially fatal effects.