Hepatitis A infection is common throughout many parts of the world and occurs most frequently in developing nations whenever there may be a lower standard of sanitation. In such countries, most of the population can be infected but paradoxically, this usually presents no significant public health problem as infection early in life is asymptomatic and provides the individual with life-long immunity. Transmission occurs mainly by the faecal-oral route and poor sanitation practices can lead to contaminated water which also allows concentration in shellfish. Infection with hepatitis A virus (HAV) is self-limiting and can produce symptoms ranging from subclinical to fulminant hepatitis. The chances of developing clinical disease can be correlated with the age at which infection occurs. In young children, most infections are asymptomatic but in older children and adults, symptoms occur commonly, most notably jaundice, fever, malaise and dark urine.