Chickenpox is highly contagious because chickenpox is universally susceptible in the population, especially in susceptible children who can develop it 90% of the time if they come in contact with a person with chickenpox, but it is less common in infants less than 6 months of age. The risk of secondary infection is very low because of the long-lasting immunity that can be acquired after having chickenpox once. The preferred treatment is antiviral therapy, which can be applied early with acyclovir or Chinese herbal medicines to clear the heat and detoxify the toxins. Special attention needs to be paid to the development of complications in treatment. There are four common complications: first, bacterial infection secondary to skin; second, pneumonia; third, encephalitis, the incidence of which is less than 1%; and fourth, hepatitis. In terms of prevention, patients need to be isolated until the rash is all crusted over and becomes dry and crusty, usually for two weeks.