1. In conscious rats provided with indwelling pancreatic and biliary catheters, the influence of anesthesia was investigated. 2. Ether was applied in concentrations of 4, 6 and 8 Vol % by an evaporator and Na-pentobarbital injected intravenously (30 mg/kg b. w.) 3. Flow rate, electrolytes (ion-selective electrodes and flame photometry), total protein concentration and the amount of several different individual enzyme fractions were determined quantitatively by electrophoresis. 4. During ether anesthesia flow rate and total protein concentration are decreased by about 50% of the control. A certain constant basal flow is established. Na+-Concentration is increased (+15%) and K+-concentration is diminished by about 30-35%. Characteristic changes in the enzyme spectrum are induced. 5. Changes due to pentobarbital anesthesia are as follows: reduction of the mean flow rate (30-35%) with large fluctuations. Corresponding variations of the K+-concentration. Diminution of the protein content without typical changes in the individual enzyme fractions.