Taking diuretics is a way to remove excess water and salt from the body, but if taken in excess, it can cause a decrease in body fluid volume, leading to a drop in blood pressure, causing many side effects including: systemic symptoms such as dizziness, lightheadedness, fainting or coma.

Diuretics are used in combination with other drugs to treat edema caused by heart failure, congestive heart failure, cirrhosis, corticosteroid and estrogen therapy, and are especially useful in cases of edema due to renal dysfunction. Although safe, diuretics can also cause unwanted side effects.