Having bloody mary on the rag Hello writers! Today is the Menstrual Hygiene Day, annual awareness day on May 28 to highlight the importance of good menstrual hygiene management at global level. This year's theme is : Action and Investment in Menstrual Hygiene and Health. Fun Fact: Why 28th May (28/5) ? Menses typically lasts 5 days. And the average menstrual cycle lasts 28 days.