Is Boba Hard to Digest?

If you type "boba makes me" into Google, it finishes the sentence with "nauseous," "poop," "bloated," and "gassy." If you type "boba stomach," the suggestions include "xray" and "blockage," and "boba constipation" brings up "chinese girl boba constipation," a story from 2019 that most boba drinkers have heard some version of.

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For most people, the pearls themselves aren't hard to digest. They're mostly starch, which your body is built to break down. They're also dense and chewy, so a pearl you swallow whole can sit in your stomach as a pearl for a while. The published cases where boba caused trouble involved either a huge amount of it or a gut that was already narrowed or slow. If boba upsets your stomach every time you drink it, the milk has a better-documented way of doing that than the pearls do.

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What the pearls are made of

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Tapioca is a starch that comes from cassava, a root vegetable, and Cleveland Clinic says that tapioca starch is what the chewy pearls in boba tea are made from. A 2025 report in Clinical Practice and Cases in Emergency Medicine (a journal where ER doctors write up unusual patients) describes the pearls as starches, brown sugar, and water that get rolled into small balls and boiled until they turn gummy and chewy, with potato starch sometimes mixed in to give them a firm finish.

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According to the NIDDK (the US government's institute for digestive diseases), digesting starch starts in your mouth, where an enzyme in your saliva begins to break starches down, and juices from your pancreas and small intestine finish the job, breaking carbohydrates into simple sugars that you absorb.

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Stanford Health Care's Digestive Health Center gives patients a low-fiber diet for ulcerative colitis, for recovery after intestinal surgery, and for a stricture (a narrowed spot in the intestines). Its list of foods to eat includes tapioca, next to white rice, pasta, and saltines. The handout doesn't mention boba, though, and nobody has published a study measuring how well cooked boba pearls get digested.

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Why pearls keep showing up on scans

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In 2017, emergency doctors at National Cheng Kung University Hospital in Taiwan wrote about an 18-year-old who came in after a traffic accident and got a CT scan (a detailed 3D X-ray). The scan showed a small tear in her liver and "multiple pearl-like lesions" in her stomach and duodenum (the first part of your small intestine). She'd had a cup of bubble tea three hours before the crash, and she had no stomachache and no "coffee ground vomitus" (vomit with old blood in it, a sign of bleeding in the stomach).

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The 2025 ER report comes from Southern Illinois University. An 11-year-old girl came in with severe pain on the lower right side of her belly, which looked like appendicitis. Her scan showed "several ingested radiopaque densities" (objects solid enough to block X-rays, so they show up bright) in her stomach, and doctors tested her for a possible overdose before her mother mentioned that she'd had bubble tea while shopping earlier that evening. She was kept overnight, and by the following morning her pain had gone away on its own, without any treatment. The report never says that the pearls caused her pain. The authors wrote it up so that other ER doctors would recognize boba on a scan and skip tests they don't need, and they admit that it isn't well understood how this food shows up at all.

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The girl with 100 pearls

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In 2019, Chinese news outlets reported that a 14-year-old in Zhejiang province had gone to the hospital after five days of constipation and stomach pain, and that her CT scan showed around 100 "unusual spherical shadows," which her doctors decided were undigested boba pearls. She told them that she'd had one cup of bubble tea five days earlier. According to Newsweek, Dr. Zhang Louzhen, who treated her, said that she had likely drunk a lot more over a long period. She was prescribed laxatives.

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Doctors in the US doubted the scan. Dr. Lina Felipez, a pediatric gastroenterologist (a doctor who treats kids' digestive systems) at Nicklaus Children's Hospital in Miami, told Live Science that the ingredients usually used in US pearls aren't "radiopaque," so they shouldn't show up on a CT. Dr. Vladimir Kushnir, a spokesperson for the American Gastroenterological Association (the main group of gut doctors in the US), told Snopes that he suspected that the pearls had some extra additive in them, one not used in the US, that made them show up on the X-ray so well. Snopes rated the story a "Mixture," because the image was authentic, but what those pearls were made of wasn't clear.

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The Illinois case undercuts part of that doubt, since that girl drank her bubble tea on an ordinary shopping trip in the US and her pearls still showed up. On the amount, Kushnir sided with the doctor who treated her. He said that the girl in China "clearly consumed an exorbitant number of bubble tea pearls," and he added, "I would reassure readers that 1-2 glasses of bubble tea are perfectly safe."

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When pearls do get stuck

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A 2025 report in the United European Gastroenterology Journal describes a 52-year-old woman in Taiwan who came to the ER with upper belly pain two hours after a lunch that included boba milk tea. Her scan showed "multiple well-defined hyperdense marble-like lesions" in her stomach and duodenum, which were stretched out. It also showed superior mesenteric artery syndrome, a condition where a large blood vessel presses on the third part of the duodenum and narrows it. The authors wrote that the narrowing might be why the tapioca pearls were held back, which means that the pearls got stuck because the path was already squeezed.

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Two other reports have titles that point the same way: a 2023 case from Montreal Children's Hospital titled "Superior mesenteric artery syndrome identified following bubble tea ingestion and duodenal impaction," and a 2025 case from Japan titled "Gastric food bolus impaction triggered by bubble tea: A rare case of pediatric gastroparesis" (gastroparesis is a condition where the stomach empties too slowly). Swallowed gum works much like this, with its rare blockages clustering in people who swallow a lot of it or whose guts already move slowly.

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The Illinois report points out that the pearls are dense and gelatinous and are meant to be chewed before you swallow them so that they digest properly, and the NIDDK's description of digestion starts with chewing, since that's when saliva first gets at the starch.

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Does boba get harder when it's cold?

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It does, which is why "why does boba get hard in fridge" is one of Google's suggestions. In a 2017 study in PLOS ONE, researchers kept cooked tapioca starch gels in a fridge for up to 28 days and found that the gels got harder the longer they were stored cold, because the starch slowly recrystallizes as it cools (a process called retrogradation). The study measured texture only, though, so whether a hardened pearl is any harder to digest is still untested.

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If boba upsets your stomach

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Look at the milk before you blame the pearls. Monash University's FODMAP program (FODMAPs are carbs that some people's guts absorb poorly and ferment into gas) says that lactose is the main FODMAP in dairy foods, and it lists cow's milk as high in it. MedlinePlus (the US National Library of Medicine's health site) says that lactase nonpersistence (making less of the enzyme that digests lactose after childhood) affects 70 to 100 percent of people of East Asian descent, against about 5 percent of people of Northern European descent. Having less of the enzyme doesn't guarantee symptoms, which the lactose intolerance article gets into.

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Felipez does put some of the blame on the pearls. She told Live Science that eating a lot of tapioca balls could "for sure" cause constipation, and that pearls often contain guar gum, a fiber that holds them together and swells in water, which she said may play a role in digestive problems.

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If you want to know which part is bothering you, change one thing at a time, the way an elimination diet does. Order the milk tea without pearls one day, and a fruit tea with pearls another, and chew the pearls when you do have them.

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Cleveland Clinic says that you should get care as soon as you notice symptoms of a bowel blockage, which include sharp stomach pains that arrive in waves, nausea and vomiting, bloating, and, if the blockage is complete, not being able to pass gas or poop.

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