Objective: The aim of this randomized, double-blind, placebo-controlled clinical trial was to evaluate the effect of dydrogesterone and calcium plus vitamin D on young women's general health. Method: One hundred and eighty students studying at Shiraz University were recruited. Students completed the General Health Questionnaires (GHQ-28) prior to participation. They were then randomly assigned to take a tablet containing either 5 mg of dydrogesterone, 500 mg of calcium plus 200 mg of vitamin D, or a placebo twice daily from the 15th to the 24th day of their menstrual cycle for 2 consecutive cycles, and to complete the same questionnaires during both the intervention cycles. Results: The effects of dydrogesterone and calcium plus vitamin D on general health scores were similar during the first month of intervention (11.41±4.28, 12.23±3.76, respectively) (p>0.05) and both of them were more effective than placebo (16.69±3.28) (p