There may be ways to manage your medications and the foods you eat to help ease your gastrointestinal symptoms and even shorten your migraine attacks. Here are some answers to common questions about diarrhea and migraine.

1. Is Diarrhea Common With Migraine Attacks?

Diarrhea isn’t a common symptom of migraine, but it definitely occurs, says Roderick Spears, MD, a neurologist and headache specialist at Penn Medicine in Philadelphia. “A smaller percentage of people will say they have diarrhea as a symptom of migraine compared to vomiting,” he says. Unlike diarrhea, nausea and vomiting are both symptoms listed in the International Headache Society Classification ICHD-3 for migraine. Diarrhea can occur as a symptom of any type of migraine; it’s not related to one specific type, says Dr. Spears.

2. What Causes Diarrhea and Headaches?

“We think that there is a connection between diarrhea and headaches, with serotonin being the common denominator,” says Spears. Serotonin is a major neurotransmitter that helps regulate mood, but there are also a lot of serotonin receptors in the gut, he explains. “In the majority of people with migraine, the gut will actually slow down during the attack and not move anything forward. In the worst-case scenario, things go in the opposite direction, and people experience vomiting, but for a smaller percentage of people, migraine will actually speed the gut up, and they develop diarrhea,” says Spears.

3. Why Do Migraine Attacks Cause Vomiting and Diarrhea?

“Sometimes nausea can turn into vomiting if the migraine isn’t stopped,” says Spears. But why vomiting or diarrhea can be part of the cascade of migraine isn’t totally clear, he says. “We know that vomiting will decrease intracranial [within the skull] pressure. There are some migraine patients, especially younger people, who tell me that if they vomit during a migraine attack, it will abort the attack,” says Spears.

4. Can Digestive Issues Cause Migraine?

It hasn’t been proven that irritable bowel syndrome (IBS) causes migraine or vice versa, says Spears, but “there is a correlation between the two conditions. If you have migraine, it seems you’re more likely to have IBS, and if you have IBS, you’re more likely to have migraine,” he says. A study published in the Polish Journal of Neurology and Neurosurgery found that 23 to 53 percent of people with IBS experienced frequent headaches, and that 10 to 20 percent of the population had both migraine and IBS. A diagnosis of IBS is different from gastrointestinal (GI) symptoms during a migraine attack, says Spears. “When a person has IBS, they are having either diarrhea, constipation, or abdominal bloating going on most of the time, and they can cycle between those different phases,” says Spears. Even if you experience those types of GI symptoms in migraine, they wouldn’t be present all the time, he explains. “Even in chronic migraine, you wouldn’t have a lot of patients in that category,” he says. Chronic migraine is when a person experiences 15 or more days per month of headache with migrainous features for at least three months, according to the Migraine Research Foundation. Episodic migraine is when a person has fewer than 15 headache days per month. RELATED: What You Need to Know About IBS and Migraine

5. Should I Limit Caffeine if I Have Migraine and Diarrhea?

People with migraine have several reasons to use caffeine with caution. One is that either too much or too little caffeine can trigger a migraine attack. Another is that ingesting too much caffeine regularly can contribute to medication-overuse headache. With regard to diarrhea, specifically, caffeine is a stimulant that increases gut motility, or the movement of food through the gastrointestinal tract, according to Michigan Health. In some people, caffeine consumption can result in loose stools or diarrhea, which can be dehydrating. Your own experience will guide your decision about whether and how much caffeine to consume during or between migraine attacks.

6. Can Dehydration From Diarrhea Affect My Headache?

If you have diarrhea and experience dehydration as a result, that could cause a headache; about 1 out of 3 people with migraine report dehydration as a trigger, according to the American Migraine Foundation. Dizziness and confusion can be a result of dehydration as well. Even in the case where diarrhea is a symptom resulting from an underlying illness or infection, it may actually be the dehydration that triggers the headache, says Spears. “If diarrhea hits after your migraine attack begins, there’s a risk that the dehydration could end up prolonging your migraine attack,” says Spears. “If you’re not able to keep liquids in your system, you might end up needing an IV to get better, which is typically given in the emergency room or an infusion suite,” he adds. RELATED: 12 Foods to Help Get Rid of a Headache or Migraine Attack Naturally

7. Could Food Sensitivities Cause Migraine and Diarrhea?

Some people believe that certain foods can trigger a migraine, but there is little evidence that a diet that eliminates certain types of foods helps to prevent migraine, according to the American Migraine Foundation. A small number of people with migraine are sensitive to gluten or have celiac disease, says Spears. “Once they figure it out and eliminate gluten from their diet, it can help prevent migraine attacks, but there aren’t a great deal of patients who fit into that category,” he adds.

8. Are Some Migraine Treatment Options Better for People Who Get Diarrhea?

“If a person is prone to diarrhea, it’s a good idea stay away from certain medications that are used preventively for migraine, such as the antidepressants SNRIs (serotonin and norepinephrine reuptake inhibitors) that may speed the gut up,” says Spears. There are potential side effects for some acute medications as well. Some over-the-counter and prescription drugs, such as Excedrin Migraine or Fioricet, contain caffeine, which may contribute to diarrhea.