Percutaneous sclerotherapy of nonparasitic cysts with ethanol or OK-432 is a technically simple and effective procedure. Only symptomatic cysts should be treated. Due to the short acquisition time, the available space for intervention, and the precise visualization of the inserted puncture systems, computed tomography (CT) is the imaging modality of choice for guiding the intervention. When indications and contraindications are properly considered, the technical and clinical success rate is high and comparable with traditional surgical procedures, while complications and mortality are lower. In addition, the method can be performed on an outpatient basis with considerably lower costs. In parasitic cysts, the risk of anaphylaxis or the spreading of protoscolices into the peritoneum in the sclerotherapy of hydatid cysts has been overestimated; however, it should not be neglected. Careful planning of the access route and periprocedural chemotherapy with mebendazole or albendazole is indispensable prior to the percutaneous treatment of hydatid cysts. Considering the proper indication, sclerotherapy of hydatid cysts with hypertonic saline or ethanol using the PAIR (Puncture-Aspiration-Injection-Reaspiration) technique has a high success rate, with clearly lower morbidity compared to surgical procedures.