Clinical studies are performed on 15 workers from the chemical and pharmaceutic plant "Stanke Dimitrov". Seven of the workers are with acute poisoning from aniline and phenylhydrazine, and eight are exposed to a chronic combined effect of a large group of organic solvents. The clinic and laboratory examinations aim at clarifying the liver and kidney functions, the state of the blood and nervous systems. The tests embrace also blood test morphology and osmotic resistance of erythrocytes, iron, correlation of haemoglobin types, electrolytes, transaminase, GGTP, lipid metabolism, iron-binding capacity. Moderately increased transaminase activity is found in 2/3 of the examined. In four of the workers is registered expressed anaemic and lung syndrome. The following diagnoses are accepted: chronic combined effect of organic solvents--in 3 workers; chronic poisoning with aniline and other solvents--in 1; toxic hepatitis--in 4, with no data for poisoning--in 7. The leading clinical syndromes in acute and chronic combined effect of organic solvents are discussed.