Acetic acid can cause cellular injury. We previously reported that acetic acid induces cancer cell-selective death in rat gastric cells. However, the mechanism is unclear. Generally, cancer cells are more sensitive to reactive oxygen species than normal cells. Accordingly, in this study, we investigated the involvement of oxidative stress in cancer cell-selective death by acetic acid using normal gastric mucosal cells and cancerous gastric mucosal cells. The cancer cell-selective death was induced at the concentration of 2–5 µM acetic acid. Cancerous gastric mucosal cells had increased expression of monocarboxylic transporter 1 and high uptake of acetic acid, compared to normal gastric mucosal cells. The exposure of cancerous gastric mucosal cells to acetic acid enhanced production of reactive oxygen species and expression of monocarboxylic transporter 1, and induced apoptosis. In contrast, acetic acid showed minor effects in normal gastric mucosal cells. These results indicate that acetic acid induced cancer cell-selective death in gastric cells through a mechanism involving oxidative stress.