Why does period poop smell so bad? Your menstruation questions answered

Period comes with a bunch of discomforts involving different systems. It can even affect the consistency and frequency of your poop. These changes in your poop can be described as 'period poop'. Is period poop even a thing, or is it all in my head? Here's all you need to know about period poop.

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Key takeaways

  • Period poop is definitely a thing and is common for many people who see their period.
  • Hormones and dietary patterns before and during your period can influence your period poop, causing it to smell bad or changing its consistency.
  • See a doctor when the symptoms become severe or unresolved after your menstruation.

Menstrual cycles are controlled by different hormones at different phases of the cycle, thereby causing some changes in the body. These changes can make periods very uncomfortable for some women, while for others, they cause little or no discomfort.

The most common symptom people experience during their period is abdominal cramp (pain), which is mostly felt in the lower abdominal region. This pain is caused by the production of a hormone called prostaglandins, which is released by the body before the start of your period.

Prostaglandin causes contractions of the smooth muscles of the uterus and helps propel the menstrual blood out of the uterus. This hormone also affects the smooth muscles of other organs, such as the gut, which it stimulates, leading to diarrhea or more pooping.

Research has shown that many women experience cyclical changes in gastrointestinal symptoms throughout their menstrual cycle, particularly alterations in bowel habits. Also, for some people, the smell of their poop at this phase of the menstrual cycle may be different, and this may be attributed to the diet before your period. 

These changes in the nature of your poop during periods are what is termed 'period poop.'

Why period poop has a very foul odor

Having foul-smelling poop during your period may be attributed to the type of food you consumed prior to your period—usually due to premenstrual cravings. 

One study found that female sex steroid hormones influence women's food intake behavior throughout their menstrual cycle. Notice that a few days before your period and even at the start of the period, there's a heightened craving for sweet foods, e.g., chocolate, candy, ice cream, etc. These cravings have been linked to the presence of increased levels of progesterone in the body prior to menstruation.

Consumption of these foods can alter the smell of your poop, making it smell bad during your period. Although it may be hard to resist the urge for those sweet foods, cutting down on their consumption may help reduce the foul smell you have during your period.

Why does period blood smell like poop?

Period blood can be unusually stinky for some people. This is due to the presence of dead tissues in the blood. Period blood isn't just blood. It contains blood, vaginal fluid, dead endometrial tissues, and bacteria from the vagina (the normal flora). The bacterial activities in the vagina may also contribute to the odor of the period blood, and this can differ from person to person.

However, having your period blood smell like poop might also be an indication that there's a problem. Conditions like recto-vaginal fistula, where there's an unusual connection between the walls of the rectum and vagina,  might result in traces of poop in your vagina, causing your period blood to have the odor of poop.

So, to be on the safer side, if you notice any unusual odor other than the smell of blood, it's best to visit a doctor for a proper examination.

What causes constipation while on your period?

Although most people experience more pooping during their period, some experience constipation instead. This is caused by another hormone called progesterone.

After ovulation, your body secretes progesterone, which is needed to prepare the uterus for fertilization. When fertilization does not occur, the endometrium is shed during menstruation.

Progesterone has a relaxing effect on the muscles. Its presence can cause slow movement of the gut, causing constipation.

To help reduce constipation during menstruation, it's best to drink enough water and consume more fruits. Also, avoiding fatty foods may help. This is because fats digest slowly and can increase the risk of constipation.

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What causes pain when pooping while on your period?

So many factors can cause pain when pooping while on your period. Some of them include:

  • Constipation: When you have constipation, you tend to strain while pooping. This can put pressure on the uterus, causing more pain. 
  • Menstrual pain: Period cramps can cause you pain when pooping because of the proximity of the uterus to the rectum. The uterine cramping can exert pain on the rectum when pooping.
  • Increased hormone level: Prostaglandin increases nerve sensation, causing heightened pain sensitivity, thereby making you feel more pain.
  • Hemorrhoids: Hemorrhoids, also called piles, are swollen veins in the lower rectum and anus. This can be caused by constipation, diarrhea, or prolonged time in the toilet.
  • Underlying medical condition: In extreme cases of pain, conditions like endometriosis and irritable bowel syndrome may be suspected because these conditions can present with excessive pain during menstruation.

Why do you have gas and diarrhea during your period?

Diarrhea during menstruation may be linked to the presence of the hormone, prostaglandin. 

Prostaglandin has been shown to cause increased motility and contraction of the gastrointestinal tract leading to more pooping or diarrhea during menstruation. Also, the hormone induces the secretion of water and electrolytes into the intestines, causing your poop to be softer than usual and, in extreme cases, turn out to be watery.

Additionally, experiencing gas or bloating during your period may be linked to high levels of progesterone. Due to the slow movement of the intestine caused by the effect of progesterone, digestion is slower and longer, resulting in a buildup of gas in the gut.

Having gas during your period might also be a result of the food you eat. Consuming gas-forming foods or fatty foods that take a longer time to digest can lead to excessive bloating during your period, thereby causing you to pass too much flatus.

When to see a doctor for menstruation issues

Changes experienced during menstruation are expected to stop after menstruation. Nevertheless, if your symptoms persist after your period, it's best to visit a gynecologist because it might be a sign of an underlying ailment. Studies have found that women with irritable bowel syndrome experience heightened rectal sensitivity, bowel habits, and abdominal pain compared to people without the condition.

Additionally, if your symptoms become unbearable even while on your period, you should consult your doctor for proper check-ups and treatment and also for referral if need be.


A study found that a higher percentage of women experience at least one primary gastrointestinal symptom either before or during their period, with abdominal pain and diarrhea being the most common. These changes are a result of hormonal influence. Therefore, it's normal to experience changes during your menstruation. 

It's worth noting that these changes differ from person to person. So, you shouldn't compare your symptoms with those of others. If your symptoms become severe or persist after menstruation, it's best to visit a doctor for a proper medical check-up.