Pumpkin Spice Latte Stomach Ache: What's in the Cup and Why It Hurts

Starbucks lists a grande hot pumpkin spice latte at 150 mg of caffeine, 14 g of fat (9 g saturated) and 50 g of sugar. It is made from milk, pumpkin spice sauce (which contains condensed skim milk), espresso, whipped cream and a spice topping¹. The caffeine is an approximate value, and the figures follow Starbucks' standard recipes, so a customized order can differ.

A tall has half the caffeine of a grande. A hot venti has the same 150 mg as a hot grande, and an iced venti has 225 mg.

Coffee. Coffee stimulates gastrin release and gastric acid secretion, and a 1999 review concluded that it promotes reflux⁶. Caffeine is only part of it. In a 1975 study in the New England Journal of Medicine, researchers measured how much stomach acid regular coffee, decaf and plain caffeine each triggered. On a cup-equivalent basis, decaf's peak response was 16.5 mEq an hour, close to regular coffee's 20.9 and about double caffeine's 8.4². Something in coffee besides the caffeine was doing much of the work.

Milk. The drink is milk-based, and the sauce adds condensed skim milk¹. Lactose intolerance can bring bloating, diarrhea, gas, nausea and abdominal pain within a few hours of milk or milk products³.

Fat. A grande has 14 g¹. Fatty food is a common suspect for reflux. In two small studies, a high-fat meal did not raise measured reflux compared with a lower-fat meal of the same calories: in 12 healthy volunteers⁷, and in 13 healthy people and 14 people with reflux disease⁸. In a third, 15 people with reflux symptoms had no more acid in the esophagus on a high-fat diet than on a low-fat diet of the same calories, but they reported reflux symptoms more often⁹.

So the usual swaps (decaf, a smaller size) cut the caffeine. They don't take out the coffee, and decaf coffee still raised acid in the 1975 study.

• Size. A tall has half the caffeine of a grande and 38 g of sugar instead of 50 g¹.
• Hot or iced. An iced venti has 225 mg of caffeine; a hot venti has 150 mg¹.
• Decaf. It lowers the caffeine, but decaf coffee still raised stomach acid nearly as much as regular coffee in the 1975 study².
• Milk. If bloating, gas or diarrhea follow within a few hours, lactose is a possible reason³.

Whatever you pick, write down what you ordered and what happened (how to keep track).

Your stomach holds acid and pepsin strong enough to digest tissue. It doesn't digest itself because the lining defends itself: a mucus and bicarbonate layer, tightly joined cells beneath it, steady blood flow, and cells that renew continuously. Injury can happen when irritants overwhelm that defense, or when the defense is already impaired¹⁰.

In a study of 8,013 adults in Japan, coffee drinkers were no more likely than non-drinkers to have stomach ulcers, duodenal ulcers or reflux damage⁵. A 1999 review found that heartburn is the symptom people most often report after coffee, and that coffee is not associated with dyspepsia⁶. Plenty of people finish a seasonal cup and never think about it again.

A U.S. National Institutes of Health page lists upper-abdominal pain and feeling too full after a meal among gastritis symptoms. Black or tarry stool, or vomit that looks like coffee grounds, can mean bleeding: get medical help right away¹¹.

If the burn sits behind your breastbone or climbs into your throat, that's reflux, and the coffee picture looks similar. The Nurses' Health Study II followed 48,308 women who started without regular reflux. Those drinking more than six servings of coffee a day had a 34% higher risk of weekly reflux symptoms than women who drank none. Tea and soda looked similar, results held with or without caffeine, and milk wasn't linked at all⁴.

One line of stomach research looks past the acid to the lining's own defenses. At its center is sulforaphane, which forms when glucoraphanin from broccoli seeds and sprouts meets an enzyme called myrosinase¹².

Nrf2, inside the stomach's own cells

Sulforaphane switches on a pathway called Nrf2, which tells cells to make their own antioxidant enzymes. In lab work on stomach-lining cells, it raised those enzymes and helped the cells resist and repair oxidative damage¹³. In mice with H. pylori-inflamed stomachs, broccoli sprouts reduced the inflammation, and the effect vanished in mice bred without the Nrf2 gene¹⁴.

That is a different angle from the acid-and-irritant view: it looks at what happens inside the lining's cells.

The 8-week trial in people

The same paper reported a trial in people. Forty-eight people with H. pylori ate 70 grams of broccoli sprouts a day for eight weeks, or alfalfa sprouts, which contain no sulforaphane. In the broccoli group, serum pepsinogens I and II, blood markers of stomach inflammation, went down, along with the breath-test and stool-test markers of infection. Not in the alfalfa group¹⁴.

Two months after people stopped, the values went back to where they started¹⁴. The effect ran on the clock of weeks, and it lasted only as long as the habit did.

Two checks on a broccoli sprout label follow from that research.

1. Both halves, named. Glucoraphanin is a relatively inert precursor. In a Johns Hopkins study, sulforaphane was 3 to 4 times more bioavailable when the broccoli's own myrosinase was still active than without it¹². In a 2026 crossover study, 16 adults took glucoraphanin from broccoli seed extract once with myrosinase from mustard seed and once without, both with vitamin C. With the enzyme, 39.8% became available as sulforaphane; without it, 18.6%¹⁵. The enzyme roughly doubled the amount.

2. An amount beside every line. A "proprietary blend" gives you nothing to check.

Per two-capsule serving¹⁶:

• 700 mg broccoli seed extract (13% glucoraphanin): the precursor, with its amount.
• 200 mg broccoli sprout extract (active myrosinase): the enzyme that does the converting.
• 100 mg mustard seed extract: mustard seed is the myrosinase source used in the 2026 study¹⁵.
• 50 mg vitamin C: the fourth and last line.

The panel states up to 30 mg sulforaphane per serving. A serving is two capsules and a pouch holds 60, which is 30 servings. The other ingredients are the vegetable capsule (HPMC), rice flour, magnesium stearate and silica: no caffeine, no milk, no sugar on the list.

The trial measured at eight weeks, and its markers drifted back within two months of stopping¹⁴. One bad morning can't tell you anything on that clock. A notebook can.

• The morning of: the time, the cup, what came before.
• The next morning: raw or quiet. Write down which.
• The plain days: note them as carefully as the sore ones.
• Once a week, for eight weeks: count the plain days.

Count only the sore mornings and every cup looks like a setback. Count the plain days too and you see which way the weeks are going. Keep whatever your doctor or dietitian arranged; nothing here changes it.

There will be another cup either way. If you want a broccoli sprout supplement whose label you can check line by line, ours is Sproutly broccoli sprout extract. Your first order is covered by a 90-day money-back guarantee, counted from confirmed delivery.

Why does a pumpkin spice latte bother my stomach more than plain coffee?

It may be the extras as well as the coffee. A grande adds milk, whipped cream, 14 g of fat and 50 g of sugar to its 150 mg of caffeine¹. Milk can bring bloating or diarrhea if lactose is the trigger³, and coffee raises stomach acid, decaf included².

Is a decaf pumpkin spice latte easier on the stomach?

Not for acid. Decaf coffee raised stomach acid nearly as much as regular coffee in the 1975 study². Decaf lowers the caffeine, and a smaller size lowers the dose; neither removes the coffee.

Can I drink coffee with gastritis?

Coffee was not linked to stomach ulcers in a study of 8,013 adults⁵, though it does raise stomach acid². How your stomach takes it depends on you, so your notebook will tell you more than any rule.

Does a pumpkin spice latte cause acid reflux or heartburn?

Coffee is linked to reflux symptoms. Women drinking more than six servings a day had a 34% higher risk of weekly symptoms than women who drank none⁴, and heartburn is the symptom people most often report after coffee⁶.

Can a pumpkin spice latte cause diarrhea?

It can if lactose is the trigger: diarrhea, bloating and gas are lactose intolerance symptoms that start within a few hours of milk or milk products³. In a review, coffee also increased rectosigmoid motor activity within 4 minutes in some people⁶.

1. Starbucks Coffee Company. Pumpkin Spice Latte, hot and iced, all sizes: nutrition and ingredients (product 418). Starbucks menu and ordering data. Accessed 23 Oct 2026. starbucks.com/menu/product/418
2. Cohen S, Booth GH Jr. Gastric acid secretion and lower-esophageal-sphincter pressure in response to coffee and caffeine. N Engl J Med. 1975;293(18):897-9. PMID 1177987
3. National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & Causes of Lactose Intolerance. Last reviewed February 2018. niddk.nih.gov
4. Mehta RS, Song M, Staller K, Chan AT. Association between beverage intake and incidence of gastroesophageal reflux symptoms. Clin Gastroenterol Hepatol. 2020;18(10):2226-2233.e4. PMID 31786327
5. Shimamoto T, Yamamichi N, Kodashima S, et al. No association of coffee consumption with gastric ulcer, duodenal ulcer, reflux esophagitis, and non-erosive reflux disease: a cross-sectional study of 8,013 healthy subjects in Japan. PLoS One. 2013;8(6):e65996. PMID 23776588
6. Boekema PJ, Samsom M, van Berge Henegouwen GP, Smout AJ. Coffee and gastrointestinal function: facts and fiction. A review. Scand J Gastroenterol Suppl. 1999;230:35-9. PMID 10499460
7. Pehl C, Waizenhoefer A, Wendl B, et al. Effect of low and high fat meals on lower esophageal sphincter motility and gastroesophageal reflux in healthy subjects. Am J Gastroenterol. 1999;94(5):1192-6. PMID 10235191
8. Penagini R, Mangano M, Bianchi PA. Effect of increasing the fat content but not the energy load of a meal on gastro-oesophageal reflux and lower oesophageal sphincter motor function. Gut. 1998;42(3):330-3. PMID 9577336
9. Fox M, Barr C, Nolan S, et al. The effects of dietary fat and calorie density on esophageal acid exposure and reflux symptoms. Clin Gastroenterol Hepatol. 2007;5(4):439-44. PMID 17363334
10. Laine L, Takeuchi K, Tarnawski A. Gastric mucosal defense and cytoprotection: bench to bedside. Gastroenterology. 2008;135(1):41-60. PMID 18549814
11. National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & Causes of Gastritis & Gastropathy. Last reviewed August 2019. niddk.nih.gov
12. Fahey JW, Holtzclaw WD, Wehage SL, et al. Sulforaphane bioavailability from glucoraphanin-rich broccoli: control by active endogenous myrosinase. PLoS One. 2015;10(11):e0140963. PMID 26524341
13. Yanaka A. Sulforaphane enhances protection and repair of gastric mucosa against oxidative stress in vitro, and demonstrates anti-inflammatory effects on Helicobacter pylori-infected gastric mucosae in mice and human subjects. Curr Pharm Des. 2011;17(16):1532-40. PMID 21548875
14. Yanaka A, Fahey JW, Fukumoto A, et al. Dietary sulforaphane-rich broccoli sprouts reduce colonization and attenuate gastritis in Helicobacter pylori-infected mice and humans. Cancer Prev Res (Phila). 2009;2(4):353-60. PMID 19349290
15. Mastaloudis A, Holcomb L, Fahey JW, et al. Exogenous myrosinase from mustard seed increases bioavailability of sulforaphane from a glucoraphanin-rich broccoli seed extract in a randomized clinical study. Sci Rep. 2026;16(1):9162. PMID 41692762
16. Sproutly Broccoli Sprout Extract Capsules, Supplement Facts panel (two-capsule serving), verified against the label photo in the Sproutly asset registry, 23 Aug 2026.