The Master Cleanse is clearly known to affect menstruation largely from thicker heavier flows.

Stanley Burroughs, inventor of The Master Cleanser, doesn't specifically say one way or another that the cleanse is safe for menstruating women but he had a special tip regarding lemon skins and the effects on menstrual periods:

Blend a part of the lemon skin and pulp with the lemonade in a blender for further cleansing and laxative effect. (Note: commercially procured lemons may have had their skins dyed with yellow coloring and may have been subjected to poisonous insect sprays— be sure to peel off the outer skin if you cannot get uncolored, organically grown lemons.) The properties in the lemon skin also act as a haemostatic to prevent excess bleeding and to prevent clotting internally should there be any such prevailing condition. (Don’t worry— normal conditions will continue during menstrual periods.)

When considering this tip, one can infer that he felt the master cleanse was perfectly safe for during menstruation.

Common Effects of The Master Cleanse on Periods

  1. Early and Late Periods: Can come early. While on the cleanse their menstrual cycle started at a different time of the month than usual
  2. Heavy Periods: If it is heavy, but you are not feeling tired, a lack of energy or weak due to the heavy flow, then also, don’t worry. Many women report discharges are often darker and heavier, but only temporarily.
  3. Missed Periods: Not commonly reported.

Tips for Master Cleansing and Menstruation

Bad Cramps? Try taking a little more than one-half teaspoon of cayenne, and  put it on the back of your tongue, and take a drink of lemonade. The cramping has been reported to stop instantly while producing an immediate elimination afterwards helping with with menstruation cramps.

If your problems don’t go away after a couple days off the cleanse, I would see a doctor. If they do go away, you might want to consider putting yourself on a health-restoring regimen for several months.