Many people suffer from undue psychological stress in modern society. We here examined whether emotional tears relieve stress and improve mood state. Fourteen healthy students were subjected to a mental arithmetic task, and were subsequently induced to shed tears by viewing emotional movie scenes or cutting onions. A resting state following the task was also used as a control. The mood states were assessed with the Profile of Mood States (POMS). Heart rate variability, especially the ratio between low and high frequency components (LF/HF ratio), was measured to evaluate levels of psychological stress. Fatigue levels of POMS and LF/HF ratio were decreased after shedding tears by viewing emotional movie scenes. In contrast, tears caused by onions, as well as resting state, resulted in little or no reduction in either fatigue levels or LF/HF ratio. These findings demonstrate that emotional tears play an important role in relieving psychological stress and reducing mental fatigue.