Multivariate path analysis was used to examine the etiologies of variation and covariation of flushing after alcohol use in nuclear families of Korean, Taiwanese, Japanese and Caucasian ancestries. Phenotypic variances and covariances were partitioned into familial (additive genetic and common family environment) and environmental components. Although alcohol consumption and flushing varied greatly among the different groups, familialities, estimated from components of mother, father and at least one child, were remarkably similar. The familialities for flushing were 0.48 for Japanese, 0.56 for Koreans and 0.35 for Taiwanese; flushing is infrequent in Caucasians and thus was not analyzed. Familialities were lower for consumption, but like flushing, were consistent across ethnic groups (Japanese, 0.27; Koreans, 0.24; Taiwanese, 0.15; Caucasians, 0.28). The genetic correlation between flushing and alcohol consumption was high. Thus, to the extent that flushing influences alcohol consumption, the covariance is most likely genetic.