Many of these chemicals are difficult for the kidneys to excrete out of the body. The liver helps by removing these chemicals from the blood stream and changing them into products that can be readily removed through the bile or urine. In this process, unstable toxic products are sometimes produced. These can attack and injure the liver. Predictable toxic chemical injury usually involves this type of mechanism.
Examples are the cleaning solvent, carbon tetrachloride, and the pain medication, acetaminophen.
When acetaminophen is taken in excessive doses, either at once or over a period of time, severe damage to the liver may occur. In fact, alcohol is by far the most common cause of toxic chemical damage to the liver in our society. The unpredictable type injury can be produced by many drugs and appears to involve an allergic reaction that is directed at the liver. Symptoms of chemical injury to the liver can resemble any form of acute or chronic liver disease. Acute liver injury can resemble viral hepatitis or blockage of the bile ducts.