Philp, J. R., T. P. Hamilton II, T. J. Albert, R. S. Stone and C. F. Pait (Orange County Health Department, P.O. Box 355, Santa Ana, California 92702). Infectious hepatitis outbreak with mai tai as the vehicle of transmission. Am J Epidemiol 97: 50–54, 1973.— Following a luau off the Southern California coast in August 1971, 99 of the 174 attendees developed infectious hepatitis. The mean incubation period was 26 days and the luau was the only common experience shared by all during the year. All hepatitis patients had drunk the mai tai punch while at least 21 of those ill had not partaken of other suspect foods. Care was taken to obtain reliable and sanitary ingredients, including using commercially bottled water, but no proper food handling was practiced. Handwashing was virtually nonexistent. The punch was served in a three-tiered fountain permitting frequent contamination by persons filling their glasses as well as contamination by persons cleaning out the pump which plugged. It is postulated that an asymptomatic carrier did not wash his hands after using the toilet and subsequently infected the punch. The necessity for proper food handling is emphasized by this unusual outbreak.