Hepatitis B is a liver infection caused by the Hepatitis B virus (HBV). HBV is transmitted through activities that involve percutaneous or mucosal contact with infectious blood or body fluids. HBV can survive outside the body at least 7 days and still be capable of causing infection. The best way to prevent hepatitis B is by getting the hepatitis B vaccine. The pathogenesis and clinical manifestations of hepatitis B are due to the interaction of the virus and the host immune system, which lead to liver injury and potentially cirrhosis and hepatocellular carcinoma. Patients can have either an acute symptomatic disease or an asymptomatic disease.

Hepatitis C is a devastating viral disease that generally progresses slowly, meaning patients often remain asymptomatic and unaware they are infected until very serious and often expensive complications emerge as a result of damage to the liver. It is estimated that about half of those infected are not aware that they carry the virus. The recent remarkable advances in treating hepatitis C built on incremental improvements achieved over the previous two decades to transform hepatitis C from a chronic, fatal disease, to an infection that with new and forthcoming treatments, can be potentially cured.

The best way to prevent hepatitis is by getting the hepatitis vaccines. Vaccination is safe and effective and it is recommended for all. Efforts to develop a hepatitis C vaccine started more than 20 years ago, when the hepatitis C virus was identified. The hepatitis C virus is more variable than are the viruses that cause hepatitis A and hepatitis B. Hepatitis C virus occurs in at least six genetically distinct forms with 50 subtypes. A global vaccine would have to protect against all these variants of the virus.

Screening for Liver diseases has been advocated with the intention of intervening to halt its progression. Abnormal liver tests are those that measure synthesis of proteins made by the liver (albumin, clotting factors) or the liver's capacity to metabolize drugs. The impact of diagnosis of hepatitis C virus on quality of life is worse in patients aware of their viral status compared with individuals unaware of their viral status.

Liver diseases are caused by metabolic, genetic drug induced and due to autoimmune diseases. Hepatic coma also known as Hepatic encephalopathy is a metabolic abnormality caused by accumulation of toxic substances in the bloodstream that are normally removed by the liver. Haemochromatosis is a genetic disorder caused by accumulation of iron in the liver. Non-alcoholic fatty liver disease is a drug induced liver disease caused by accumulation of extra fat in liver cells that is not caused by alcohol, whereas Alcoholic liver disease is due to overconsumption of alcohol. Primary biliary cirrhosis is an autoimmune disease of the liver in which the bile ducts in liver are slowly destroyed.

Hepatocellular carcinoma is the most common form of liver cancer in adults. It begins in the hepatocytes, the main type of liver cell. The production of cancer cells in the Liver is called hepato-carcinogenesis. Research is going on to develop drugs that builds liver cancer immunity and also identifying and understanding cancer stem cells and their properties to develop effective anti-cancer therapies.

Several disorders contribute to liver disease in pregnancy such as acute fatty liver of pregnancy (AFLP) and intrahepatic cholestasis of pregnancy (IHCP), hyperemesis gravidarum and hemolysis and elevated liver enzymes and low platelets (HELLP) syndrome. Liver disease such as acute viral hepatitis can occur in pregnancy and pregnancy may occur in a patient with underlying chronic liver disease including patients with cirrhosis and portal hypertension, and patients who have undergone liver transplantation.

Non-viral hepatitis is an inflammation of the liver caused by toxins, drugs, or other harmful chemicals that destroy cells in the liver (Hepatocytes). Acute hepatitis damages hepatocytes, make up 70-85% of the total mass of the liver. The disease is a growing problem due to the increasing number of dietary supplements with liver side effects. If hepatitis leads to liver failure, a liver transplant is the only treatment option that can improve survival.

In recent years, tremendous research advances are transforming treatment of Hepatitis. More than 90% of patients with the most common form of the disease can expect to be cured in as little as 8 weeks with newly approved antiviral therapies. More new medicines are on the way. Most of this progress has occurred in just the last three years with newer and more effective therapies transforming the trajectory of the disease for many patients. The scientific advances made in recent years by biopharmaceutical researchers as they combat the hepatitis C virus have already begun to have a tangible impact on thousands of patients.

Liver transplantation is the only treatment possible option for end-stage liver disease and acute liver failure. Research is going on development of artificial liver support, a technology based on artificial materials for partial replacement of liver function. Liver surgery comprises various operations of the liver for different disorders. The most common operation performed on the liver is a resection (removal of a portion of the liver).

There are many inherited metabolic and genetic disorders that may have a pathologic impact on the liver. Haemochromatosis, Gilbert syndrome and Wilson’s disease are genetic disorders caused by accumulation of iron, bilirubin and copper in the liver. Alpha1-antitrypsin (α1-AT) deficiency is a disorder in which the normal processing of a liver-produced protein is disturbed within the liver cell.