We have recently studied the electric activity of the liver in both a normal canine model and in humans, and could characterize an electrohepatogram (EHG). Regular and reproducible slow waves or pacesetter potentials (PPs) were recorded. Hepatoarrhythmic electric activity was registered in liver insult of a canine model and in liver cirrhosis. The current communication studied the hepatic electric activity in liver diseases aiming at identifying an EHG for the different pathologic conditions, to be used as an investigative tool in their diagnosis. 55 subjects were studied: 10 with hepatocellular cancer (7 men, 3 women; age 53.7 years), 16 with acute hepatitis (10 men, 6 women; 42.2 years), 14 with metastatic liver deposits (9 men, 5 women; 53.1 years), and 15 healthy volunteers as controls (10 men, 5 women, 43.6 years). Three electrodes were placed 1.5 - 2 cm below and parallel to the costal margin and 4 to 5 cm apart. They were connected to a Beckman R611 recorder. At least two 20-minute recording sessions were performed for each subject. The PPs of the healthy volunteers exhibited a regular rhythm with identical and reproducible frequency and amplitude from the3 electrodes in the same subject. The EHG of the hepatocellular cancer patients showed a 'hepatoarrhythmic' pattern; the waves had irregular frequency and amplitude. In acute hepatitis 2 patterns were encountered: 'silent', which occurred in the preicteric and icteric stages, and 'hepatoarrhythmic' which occurred in the convalescent stage. The liver which had a few metastatic deposits exhibited a hepatoarrhythmic pattern and the liver with numerous deposits presented a 'silent' pattern. The aforementioned patterns were reproducible. In conclusion, different patterns were recorded in the various liver diseases. The patterns seem to reflect the liver cell function. A normal EHG was recorded from the healthy liver, while a silent EHG was registered from the presumably non-functioning liver cells. Hepatoarrhythmia occurred probably when the liver function was impaired. Electrohepatograhy is a simple, easy, non-invasive, and non-radiologic procedure. It is suggested to serve as an investigative tool in the diagnosis of liver diseases.