In the study on the Donaggio values before and after various surgical operations the author obtained the following results. 1. In the appendectomy the average urine Donaggio value before operation is 2, and 18.7 after the operation. 2. In the operation for gastric cancer or gastric ulcers, the average of the urinc Donaggio values before the operation is 10.7 while it is 24.0 after the operation. 3. In the operation for hernia and pile the urine Donaggio values both before and after the operation do not show any difference.