Objectives: Owing to the recent rapid advancements in image processing and three-dimensional (3-D) technologies, stereoscopic images can now be viewed on television as well as in theaters and on gaming consoles among others. However, with these advancements, there have also been reports on motion sickness and asthenopia induced by viewing stereoscopic films. Human equilibrium function deteriorates when viewing stereoscopic films, which may lead to motion sickness; however, the exact cause of such motion sickness remains unknown. Therefore, as part of hygiene research that contributes to society, it is important to consider the safety of viewing virtual 3D contents. Methods: In this study, we investigated the effects of viewing 2-D/3-D video clips on the human body by stabilometry, electrogastrography (EGG), and subjective assessments. Seven subjects aged 22 to 24 viewed 2-D/3-D video clips for 60 min. Results: A comparison of time series data obtained at rest shows a significant change in the EGG patterns 20 min after the start of viewing the video clips. Furthermore, sway values while viewing the 3-D video clips were considerably higher than those while viewing the 2-D video clips 60 min after the start of viewing. Conclusions: These findings show that the autonomic nervous system is affected first by long-term viewing of stereoscopic films, and the equilibrium function deteriorates gradually over the course of the exposure.