OK TMI: Why Do I *Always* Get Diarrhea on My Period?

Everyone talks about feeling moody before their period. But can we also talk about the bathroom situation? What’s up with those gnarly period poops?

Gut-related symptoms are included in the PMS package (file it under “unexpected period symptoms“) for nearly half of people with periods, according to a 2020 paper in Women and Health. That includes more frequent trips to the bathroom and—you guessed it—diarrhea. But what is period diarrhea, exactly (like, why)? We’ll explain that here, along with how to cope.

What causes diarrhea before or during your period?

Diarrhea before or during your period all comes down to the hormone changes happening during this time of your cycle. The main culprit is hormone-like substances called prostaglandins—or chemical signals produced by your uterus around the time of your period. “They can induce pain and cramping. They can also act on your gut and cause diarrhea-like symptoms,” says Tiffany Pham, MD, OB/GYN, and Flo medical advisor.

Estrogen and progesterone factor in, too. Shifts in these hormones can trigger changes in your neurotransmitter serotonin, “which can play a role in your gut motility, potentially leading to diarrhea,” adds Dr. Pham.

Lots of people get hit with period diarrhea, but you might be more prone to the problem—or have more severe symptoms—if you have a chronic GI condition, per the Cleveland Clinic. (Think: irritable bowel syndrome (IBS) or an inflammatory bowel disease (IBD) like Crohn’s disease or ulcerative colitis.)

Other period symptoms

Chances are that diarrhea isn’t happening in a vacuum. According to the American College of Obstetricians and Gynecologists (ACOG), it’s totally normal to have a host of symptoms before your period including the following:

• Gas (watch out for those period farts!)
• Bloating and water weight gain
• Nausea
• Breast tenderness
• Headaches
• Fatigue
• Abdominal pain or cramping
• Breakouts
• Muscle or body aches
• An uptick in anxiety, irritability, or depression
• Trouble concentrating
• Trouble sleeping

How long does period-related diarrhea last?

Like other PMS symptoms, period diarrhea usually lasts for a couple days max. “It often starts just before or at the onset of menstruation and subsides as menstrual flow decreases. It shouldn’t last for more than three days,” says Melanie Bone, MD, OB/GYN, and U.S. medical director at Daye.

Basically, those symptom-triggering prostaglandins are peaking right as your period starts. They start to drop as the lining of your uterus continues to shed, per the ACOG. And as they fall, your period symptoms start to ease up.

How to stop diarrhea on your period

There are a couple things you can do to get your bathroom situation under control during menstruation. Here are some tips to treat period diarrhea:

Avoid foods that worsen diarrhea

First, pay attention to your diet and avoid adding fuel to your gastrointestinal fire. “Avoid foods that can worsen diarrhea, such as caffeine, dairy products, spicy foods, and very sugary foods,” says Dr. Bone. Instead, stick with as many whole foods as you can—like fruits and vegetables, whole grains, healthy fats, and lean proteins. It’ll help support regular bowel movements and keep you feeling your best overall, per the Cleveland Clinic.

Stay hydrated

You should also try to stay hydrated by drinking plenty of water and including foods or drinks with electrolytes like sodium and potassium. Broth, sports drinks, and bananas are good choices for these, according to the International Foundation for Gastrointestinal Disorders (IFFGD).

Try over-the-counter meds

If your diarrhea doesn’t subside from these methods, reach for an over-the-counter (OTC) medicine if you need some extra help. An anti-diarrheal like Imodium will slow the flow of runny poop on your period, so you’re not running to the bathroom nonstop, adds Dr. Bone. NSAIDs like ibuprofen can also be useful, because they curb the inflammatory effect of prostaglandins, she adds. They have the added benefit of easing cramps, too.

Implement other healthy habits

Other healthy habits can make a difference, too. Getting enough sleep, exercising, and just taking some time to relax can go a long way towards making your PMS symptoms as a whole more manageable, per the ACOG.

Consider birth control options

That said, let your doctor know if your symptoms get to the point where they’re affecting your well-being every month. Hormonal birth control options (including the pill, patch, ring, or hormonal IUDs or injections) can make a difference by keeping hormone swings in check, per the ACOG.

When to see a doctor

Overall, diarrhea is normal during your period. But let your gynecologist know if your period symptoms seem intense or if diarrhea that hits around your “time of month” is interfering with your day to day. While some people have worse PMS symptoms than others, they shouldn’t be to the point where they’re affecting your quality of life, says Dr. Pham. Your doctor might also recommend getting checked for a GI condition like IBS or IBD, which could be driving the diarrhea, too.

FAQ

Does Midol help with diarrhea?

It might. Midol is an NSAID pain reliever, so it works similarly to other OTC pain meds to reduce the inflammation caused by high levels of prostaglandins. (Just remember to take either Midol or another NSAID, but not both at the same time.) Curbing this inflammation can control your diarrhea, but just keep in mind: it can sometimes work a little too well and end up making you constipated, per Drugs.com. Make sure you’re drinking plenty of water and eating a balanced diet while on Midol to help regulate your bowels.

And if Midol does not help, you can also take Imodium to help stop the flow of loose stool—which could potentially relieve pain and upset stomach, too.

Why do you poop a lot on your period?

Pooping a lot on your period is most likely due to an increase in prostaglandins—the chemical signals that help your uterus shed its lining, per the Cleveland Clinic. They essentially have the same move-it-along effect on your gut, which can make you poop more or give you diarrhea.

Can your period cause constipation?

It can. While an increase in prostaglandins can make you poop more, higher levels of progesterone (which helps make your uterine lining thicker before your period) can slow the movement of stool through your GI tract and make you constipated, per the Cleveland Clinic. This may be while you feel constipation and cramps at the same time.

—medically reviewed by Andrea Braden, MD, OB/GYN