Periods rarely come alone: pain, fatigue, and often... digestive issues. Menstrual diarrhea is a very common symptom, yet still taboo. We dare to say we have a stomach bug, but rarely that our period "messes up our stomach".
Why does this phenomenon happen? Is it normal? And above all, how to adapt your diet to avoid it? Complete scientific explanations.
Menstrual diarrhea is caused by prostaglandins, hormones that stimulate contractions in the uterus but also in the intestines. To avoid it, limit "Omega-6" fats (deli meats, industrial oils) before your period and favor rice and cooked vegetables. Regarding hygiene, a stemless internal period product is recommended to avoid contact between flows.
Article Summary
1- Frequency: You are not alone (The numbers)
If you spend your time in the bathroom during your period, rest assured: it's physiological.
A reference study (1) showed that 73% of menstruating people suffer from digestive issues during their cycle:
- 28% have diarrhea during their period.
- 24% suffer from it just before (PMS).
It is therefore not a "weakness" on your part, but a mechanical reaction of your body.
2- The biological cause: Prostaglandins
The culprit has a name: Prostaglandins. These are messenger hormones produced by the endometrium (the lining of the uterus) just before your period.
Their mission: To order the uterus to contract to expel blood and tissues. This is necessary.
The problem: These hormones pass into the blood and do not always aim very accurately. They reach neighboring organs, notably the intestines. The smooth muscles of your digestive system then also receive the order to contract ("Contract!").
👉 Result: Transit speeds up suddenly, causing intestinal cramps and diarrhea.
3- Diet: Which foods to avoid before your period?
Prostaglandins are manufactured by your body from certain fats (fatty acids) that you eat. By limiting these specific fats a few days before your period, you can reduce the production of prostaglandins, and thus diarrhea.
These are mainly Omega-6s (Arachidonic acid and Linoleic acid). They are excellent for your health normally, but "pro-inflammatory" in excess before your period.
| ❌ To limit before your period (Rich in Omega-6) | ✅ To favor (Digestive gentleness) |
|---|---|
| Meats & Deli meats: Andouillette, duck, pigeon, dry sausage, fatty red meat. | "White" starches: White rice, pasta, potatoes (slow down transit). |
| Oils & Seeds: Grapeseed, sunflower, corn, soy oil. Poppy seeds, pine nuts. | Cooked vegetables: Carrots, zucchini (gentle fibers). |
| Processed foods: Industrial cakes, quiches, rich dishes with sauce. | Hydration: Water, herbal teas (to compensate for fluid loss). |
Note: Eggs and fatty fish also contain arachidonic acid, but they are rich in Vitamin D (pain relief), so they shouldn't be totally banned unless in severe crisis.
4- Hygiene focus: Which product to choose?
Let's be pragmatic: managing two simultaneous flows is uncomfortable.
- Pads: They create a mixture of flows and maintain humidity, which can promote anal irritation already sensitized by frequent bowel movements.
- Tampons and ordinary cups: The tampon string or the cup stem can be soiled during wiping, which poses an obvious hygiene problem (E. Coli bacteria).
The optimal solution: Opt for a stemless internal product like La Cup Luneale.
- It hermetically separates the menstrual flow from the rest.
- The absence of an external stem makes wiping easier and guarantees impeccable hygiene.
- You can have a bowel movement without needing to remove it (contrary to popular belief).
5- The special case of Endometriosis
Sometimes, cyclic digestive issues hide something else. If the diarrhea is:
- Extremely painful (to the point of crying or fainting),
- Alternating with severe constipation,
- Accompanied by blood in the stool during your period (rectal bleeding),
- Associated with pain during defecation...
... this could be a sign of bowel endometriosis (endometrial tissue grows on the intestine or rectum). In this case, anti-diarrheal medications will not be enough: consult a specialist gynecologist.
6- What if it's constipation?
Conversely, before your period (during PMS), the sudden drop in hormones (progesterone) can slow down transit in some people.
The opposite solution: Here, you need to boost transit.
- Fibers: Prunes, almonds, legumes (lentils, chickpeas), whole grains.
- Magnesium: 70% dark chocolate is your best friend (it helps with muscle relaxation and transit).
- Water: Essential for hydrating stools.
To go further:
The composition of period blood: an incredible resource
9 natural solutions to fight period pain
(1) Bernstein et al., Gastrointestinal symptoms before and during menses, BMC Women's Health, 2014
Note: We use inclusive writing because not all women have periods, and not all people who have periods are women. However, to be visible on search engines, we sometimes use the term "women" in our articles.
