A yeast hydrolysate SCP-20 with anti-stress and mitigative effects for premenstrual syndromes (PMS) was composed with crude protein (57.5%) and carbohydrates (28.1%). For the investigation of anti-stress effect in the immobilization stressed rats, the weights of spleen, thyroid and kidney in the group of SCP-20 sdministration were significantly different from those in the group not given SCP-20. Total power (TP), suppression indicator of stress, was obtained from frequency of heart rate variability. TP was changed by the administration of SCP-20 suggesting that SCP-20 has the autonomous nervous control effect. In premenstrual assessment form(PAF), the administration of SCP-20 reduced the intensity of somatic symptoms, emotional symptoms, and behavioral symptoms.