Early morning sputum (n = 46), sputum and bronchial secretion obtained by aspiration (n = 87), pleural, ascitic, and pericardial fluids (n = 53), and pulmonary aspirate and gastric wash-out fluid (n = 10) were investigated cytologicallly using stain-covered glass slides (Testsimplets, Boehringer Mannheim). It was shown that the method was equal to classical cytological stains (Pappeheim and Papanicolaou) when exudates and biopsy material were investigated. The method is suitable for diagnostic purposes in hospitals and practice.