Drug-induced hepatitis also known as "drug-induced hepatoxicity" or "drug-induced liver disease" or "medication-induced hepatitis" is a medical condition that is characterized by the inflammation of the liver and in this case it is caused by prescription and non-prescription drugs or medications and their byproducts. Hormones, vitamins, illicit drugs and environmental toxins can also cause this type of hepatitis.

It occurs when the liver reacts to certain type of drugs; some of these drugs that cause this reactions are very toxic to the liver and they include all forms of painkillers especially Acetaminophen (paracetamol), birth control pills, amidarone, anabolic steroids, erythromycin, sulfa antibiotics, general anesthetic halothane and methotrexate.

Prescription drugs that can cause serious injury to the liver thereby leading to this condition are statin drugs (used to treat high cholesterol), the combination drug Augmentin (which is a combination of amoxicillin and clavulanate), phenytoin, azathioprine, niacin, ketoconazole and certain antivirals and anabolic steroids.

Other over-the-counter pain relievers (non-prescription drugs) that can cause this condition are Tylenol, aspirin, ibuprofen, naproxen, etc. These drugs can damage the liver especially if they are taken frequently or they are combined with alcohol. The list is long because more than 900 drugs have been known to cause liver injury.

Metabolites formed while the body processes these drugs (also known as by-products) can trigger immune responses that can lead to inflammation of the liver; these responses can occur after the first use (within hours or days of exposure) of these drugs or after repeated exposure to these drugs (like months of regular use).

The liver is the most important and largest organ of the body; it is one and once anything goes wrong with it, it can lead to serious health complications and even death because there is no second liver to replace and do the function of two like the kidneys. The many important functions of the liver are production of bile which aids in digestion, filtering and excretion of toxins from the body, excretion of bilirubin, cholesterol, hormones and drugs, breakdown of fats, proteins and carbohydrates, activation of enzymes, production of hormones, storage of glycogen, minerals and fat soluble vitamin (A, D, E and K); synthesis of clotting factors and blood proteins like albumin.