Does marijuana affect the liver? If so, can it cause problems in people infected with the hepatitis C virus?

L.V.

There is no evidence that marijuana itself leads to liver disease or damage. However, you must keep in mind that marijuana frequently contains impurities such as fungi and/or other potentially toxic plant material. It is these unknown substances that may taint this illegal and unregulated drug and may lead to significant liver injury.

Liver damage can stem from a wide spectrum of causes, including alcohol, infections (bacteria, viruses, fungi), drugs (prescription, over-the-counter, illegal), industrial chemicals and even certain herbal remedies. Although anyone who comes in contact with a potentially injurious compound may suffer life-threatening liver damage, the risk is much higher in someone with existing liver disease, such as that caused by chronic hepatitis C.

The hepatitis C virus (HCV) is primarily spread through blood-to-blood contact. In most cases, the infection becomes chronic, with inflammation in the liver of affected patients. Although patients with chronic hepatitis C may suffer complications of scarring, cirrhosis and end-stage liver disease, these complications typically occur in a small percentage of patients, and then only after many years of infection.

The progression of hepatitis C can be made significantly worse by the addition of other damaging insults to the liver. For example, it is well known that alcohol use by patients with HCV makes the disease progress much more rapidly and aggressively than is expected in the absence of alcohol use. Thus, it is prudent for any patient with HCV to use extra care in avoiding any further potential liver toxins.