Drinking too much water rarely causes overhydration because normal kidneys easily excrete excess water. Often, no symptoms occur, but in severe overhydration, people may become confused or have seizures. Fluid intake is restricted, and diuretics may be given.

Can you have a seizure from drinking too much water?

A buildup of fluid in the brain is called cerebral edema. This can affect the brain stem and cause central nervous system dysfunction. In severe cases, water intoxication can cause seizures, brain damage, a coma, and even death.

How much water can cause seizures?

For example, three patients who consumed large amounts of water experienced seizures, even though their epilepsy previously had been well controlled, according to a letter in the New England Journal of Medicine. The amounts were signficant--up to six liters a day (or approximately 1.5 gallons).