Spironolactone is an economical potassium-sparing diuretic with an anti-androgenic effect and a good safety profile. Our experience suggests that this diuretic is underexploited in dermatology even though there is evidence supporting its use in several skin conditions. When prescribed for acne in female patients (level 1–2 evidence; strength of recommendation, B), for example, it can reduce the need for antibiotics and possibly isotretinoin. Other diseases in which spironolactone is potentially useful are hidradenitis suppurativa and female androgenetic alopecia. We discuss the indications for spironolactone, dosing in dermatology, precautions to consider, and adverse effects. We also review new evidence that stresses the safety of long-term therapy and supports the use of this drug without the need for complementary testing in young women. We think that spironolactone merits a place among the medications commonly used in routine clinical practice.