This article contributes to the ever-increasing body of research on online health information-seeking behaviour. Specifically, this study shows that national culture is a determinant of trust in online health information. A questionnaire-based survey collected the data from undergraduate students on the factors influencing their trust formation toward online health information. The cultural comparisons revealed differences between the trust formations of Americans, Chinese and South Koreans in the online health environment. The trust formation of the Chinese group was based on the three factors of information quality, information style and information verification. For the American group, the information quality, information style, ease of use and information verification were the four antecedents of trust. The South Korean group considered more clues during their trust formation process than the Chinese and American groups did. Furthermore, information verification was a stronger predictor of trust for the South Korean group. The findings were discussed in light of national culture theories, and the future research agenda was presented.