They say the gut is the “second brain.” If that’s true, it’s no wonder some people’s migraine symptoms have them running to the bathroom. If you’ve ever wondered, “Why do I poop so much when I have a migraine?”, then you’ve come to the right place.

Migraine affects everyone in different ways. While some have diarrhea, others may have constipation. And some may not have any digestive changes.

So what really happens in the digestive system during a migraine attack? And why do some people feel the urge to poop?

The Gut-Brain Connection in Migraine

The relationship between the digestive system and the brain is known as the gut-brain axis. This means the brain and digestive system are closely linked. Nerves, hormones, and other signals send messages from one organ to the other, causing an intense activation of the autonomic nervous system, which controls heart rate, blood pressure, sweating, nausea, and gut motility.

Migraine attacks increase stress signals in the brain that can affect other parts of the body, including the gut. That’s why nausea, vomiting, and bowel changes are some of the most common signs of a migraine episode.

While more research is needed to fully understand how migraine impacts digestion, one theory is that migraine impacts gut motility (how fast waste moves through the intestines). Faster motility can cause cramps and send you to the toilet.

In addition, migraine affects chemical messengers in the brain, like serotonin. Serotonin also plays an important role in digestion. Since the gut is heavily influenced by serotonin, shifts during a migraine attack can cause bowel changes.

Overlapping Triggers

Some people have specific triggers that lead to migraine attacks. In some cases, migraine triggers also cause bowel symptoms. For instance, hormonal shifts (including menstrual periods) are a common migraine trigger. That “time of the month” can also increase bowel movements.

MyMigraineTeam members have also noticed diarrhea during migraine attacks when they’re sick. Getting a cold or virus can be a stressor that puts you at risk of a migraine attack. It can also cause diarrhea.

Other Factors That Can Play a Role

Many factors can trigger the urge to have a bowel movement. It may be related to migraine or a separate issue altogether.

Migraine Medication and Supplements

Some members of MyMigraineTeam have had diarrhea from taking magnesium. Although magnesium is a popular supplement for migraine, diarrhea is a common side effect. The same goes for caffeine.

There’s also a chance that your migraine treatment is causing bowel issues. Ask your healthcare provider if your medication may be causing a sudden urge to go. They can suggest ways to manage this side effect or potentially switch you to a different treatment.

Digestive System Disorders

People with migraine are more likely to have certain gastrointestinal disorders. In fact, they’re over four times more likely to have irritable bowel syndrome than those without migraine.

Inflammatory bowel disease (IBD) is another type of digestive disorder. Studies suggest that people with migraine have a roughly 30 percent higher risk of developing IBD than others.

When To Seek Help

Occasional bowel changes during a migraine attack may be normal. However, seek urgent care if you have bloody diarrhea, a fever, or diarrhea that continues for more than a few days.

If your symptoms seem to be linked to migraine, talk to a healthcare professional. They can work with you to come up with a plan, which may include:

• Adjusting your migraine medication
• Avoiding caffeine
• Changing your diet
• Using over-the-counter treatments for diarrhea

Be sure to run any lifestyle changes by your healthcare team. Even if they seem small (like drinking less coffee), they could affect your migraine treatment plan. It’s best to take a team approach to keep migraine under control.

Join the Conversation

On MyMigraineTeam, people share their experiences with migraine, get advice, and find support from others who understand.

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