water pill

noun

, Informal.

1. a diuretic pill.

Example Sentences

Diuretics, or “water pills,” are among the most common and most dangerous drugs used by bodybuilders.

From Washington Post

Diuretics - sometimes called "water pills" - increase the amount of water the body expels.

From BBC

Taking such water pills in the evening might lead to excessive urination during the night.

From Seattle Times

The other choice is water pills, but my doctor hates using diuretics.

From Seattle Times

Doctors sometimes prescribe diuretics, but taking a water pill too late in the day might actually increase nighttime urination.

From Seattle Times