Marina Sarris

Date Published: March 10, 2026

Gabriel has struggled with gastrointestinal problems that have sent him to the hospital or kept him home from school at times.

Chronic constipation and abdominal pain interfere with the 12-year-old’s daily life, say his parents, Jorge Rivera and Imayrin Padua. Sometimes, when the pain becomes too much, he stops eating. “We see him suffer, so we suffer a lot with him,” Padua says.

Gabriel is one of many children and adults with autism who have frequent or chronic gastrointestinal (GI) problems or disorders. Common GI complaints include constipation, diarrhea, excessive gas, and abdominal pain.

“It’s such a widespread concern for families of autistic children,” says Cynthia E. Brown, Ph.D., who has researched this issue in youth in the SPARK autism study.

How Common Are GI Problems in Autism?

Studies offer a wide range of estimates of how many autistic people are affected by GI problems. This range is wide likely due to different study methods.¹

A group of researchers analyzed studies involving a total of more than 23,000 autistic people. They concluded that 41 percent of children and teenagers, and 32 percent of adults, have GI problems, such as stomach pain and constipation. Also, 21 percent of autistic people, mostly adults, have been diagnosed with a GI disorder.²

GI disorders are medical conditions that affect the digestive tract, such as gastroesophageal reflux disease (chronic heartburn), irritable bowel syndrome (IBS), and inflammatory bowel disorder.

How Do GI Problems Affect Autistic People?

A research team led by Brown, a clinical child psychologist at Pacific University, examined the effect of six GI symptoms on the daily lives of autistic youth.³

Her team surveyed parents of 2,142 children and teenagers in SPARK. Parents reported that, in the previous week, GI symptoms interfered with their children’s daily activities “very often” (2 percent), “often” (7 percent), “sometimes” (24 percent), or “occasionally” (33 percent). Daily activities could include school, recreation, and play, Brown explains. Parents said that abdominal pain interfered the most with their child’s daily activities.³

More than half of the youth experienced constipation in the previous week. Curiously, their parents did not report more pain in those children. That may be because youth “may struggle with communicating and describing pain” to their parents, according to the study.³

Some autistic youth do not speak fluently. Even those who speak may not tell anyone about their GI problems or may not describe their symptoms clearly, according to a different study.⁴

One mother said her daughter became aggressive when having GI problems, a reaction that researchers called extreme. “Every time the police had to come out because she was really being destructive, first thing she would say as she regained her composure was, ‘my tummy hurts,'” that mother said.⁴

Gabriel’s parents are experts at reading his behavior for clues because he does not speak. “We just go by observation. We watch him closely and observe his behavior,” says Padua, who serves on the SPARK Community Advisory Council with her husband, Rivera.

The Massachusetts couple took their son to the hospital in 2025 after noticing signs of serious GI distress. “He was holding his stomach, and you could tell by his face he was in a lot of pain,” Padua says.

“He stopped eating,” Rivera adds.

“That’s how you know the pain is bad,” Padua says.

What’s the Link Between Autism and GI Problems?

Doctors and researchers have several theories about why GI problems are more common in autistic youth than their typically developing classmates.

Some common traits of autism may affect what people eat, which can cause or worsen GI problems.

For example, many autistic people have sensory sensitivities that may affect their ability to tolerate food of certain textures, smells, or appearances. Another trait, called insistence on sameness, may cause some people to prefer eating the same food for every meal. Both traits may result in picky eating so significant that people do not get enough fiber, water, and nutrients. This could contribute to GI problems such as constipation or indigestion.

Like many autistic children, Gabriel will only eat pizza and chicken nuggets or tenders, and drink juice. His parents encourage him to drink water and try different foods.

Autistic people may have limited diets for other reasons. A study of autistic people in SPARK found that one in five were at high risk for having a form of picky eating called avoidant/restrictive food intake disorder. Genetics may be a cause of that disorder.⁵

Genetics may also play a more direct role in GI problems for some on the autism spectrum. Some genes known to cause autism also cause GI problems. Rare variations in the genes SYNGAP1, CHD8, and DYRK1A affect nerve cells in the gut.⁶

Some of the medications prescribed to autistic people – for seizures, ADHD, or psychiatric conditions – may cause GI symptoms as a side effect. Even over-the-counter supplements like fish oil and probiotics “have known potential gastrointestinal side-effects.”^7,8

Researchers also have found a link between GI problems and mental health conditions, such as anxiety and depression, which are also common in autistic people.

How Are GI Symptoms in Autism Treated?

GI problems in autistic people are treated similarly to those in other people. But doctors who are unfamiliar with autism may find it more challenging to assess and diagnose someone who cannot describe their symptoms or whose sensory differences affect a physical exam.

Two GI doctors, Timothy Buie, M.D., and Kara Margolis, M.D., offered advice to doctors in a medical journal article in 2024. An autistic child may not show distress during exams due to “poor sensory perception,” they stated. Doctors should not rule out a GI diagnosis just because the patient did not react in a typical way.⁸

They also encouraged doctors to consider other medical problems. Some patients have seen their GI symptoms improve when they were treated for environmental allergies, ear infections, and headaches, they said.

Families often ask about diets and therapies for GI problems. Buie and Margolis did not recommend probiotics or fecal transplants of donor feces, because there is not sufficient evidence for them. Anecdotally, they said, some patients say they benefit from various special diets, but it’s not clear why. People who want to try a particular diet should work with a nutritionist, they advised.⁸

Hoping for Answers

Gabriel’s parents continued to search for medical answers. In 2026, he underwent an endoscopy, a non-surgical procedure to examine his GI tract with a camera. During the procedure, his doctor found that Gabriel has eosinophilic esophagitis, a chronic inflammation of the tube that connects the throat to the stomach. Medication can treat it, Rivera says.

Interested in joining SPARK? Here’s what you should know.

Photo credit: iStock

References

1. Holingue C. et al. Autism Res. 11, 24-36 (2018) PubMed
2. Micai M. et al. Neurosci. Biobehav. Rev. 155, 105436 (2023) PubMed
3. Ramsey T.E. et al. Res. Autism 131, 202786 (2026) Abstract
4. Holingue C. et al. Autism 26, 1698-1711 (2022) PubMed
5. Koomar T. et al. Front. Psychiatry 12, 668297 (2021) Article
6. McCluskey K.E. et al. Nat. Commun. 16, 2238 (2025) PubMed
7. Hung L.Y. and K.G. Margolis Nat. Rev. Gastroenterol. Hepatol. 21, 142-163 (2024) PubMed
8. Buie T. and K. Margolis Lancet Gastroenterol. Hepatol. 9, 684-686 (2024) PubMed