The aim of this study was to investigate the effect of diet enriched with whole grains and grains with bran on the severity of symptoms of premenstrual syndrome in nurses as a randomized controlled clinical trial on 100 nurses with premenstrual syndrome. Inclusion criteria include ages 18 to 45, regular menstruation cycles of 21 to 35 days, bleeding times of 3 to 8 days, and exclusion criteria, including diseases and interventions that affect PMS symptoms, use Of hormones and antidepressant drugs, regular exercise, BMI of over 39, alcoholics and smokers, the death of close relatives over the past six months. According to these criteria, nurses will be assigned to two groups of intervention and control groups. Individuals in the intervention group will change their daily cereals to whole grains and grains with bran for a period of three months, and in order to provide at least four serving of whole grains daily, one loaf of 120 volumes of lavax bread will be provided free of charge, And individual in the control group will continue to have regular cereals in their diet. Finally, by comparing the mean scores obtained before and after the intervention, the effectiveness of this method will be determined by the number of servings eaten.