The present invention provides an agent for preventing or suppressing hepatic dysfunction which may be taken daily and continuously, has excellent safety, and is capable of effectively preventing and/or suppressing hepatic dysfunction, such as hepatocellular necrosis, and functional food, such as foods for specified health uses, for preventing or suppressing hepatic dysfunction containing this agent. The agent for preventing or suppressing hepatic dysfunction of the present invention contains whey as the active component, and the functional food for preventing or suppressing hepatic dysfunction contains the agent for preventing or suppressing hepatic dysfunction.