Does acai cause diarrhea, bloating or constipation?

No published human trial of acai tracked diarrhea, gas or constipation as an outcome, so there's no study to point to either way — the trials that exist measured blood markers like glucose and cholesterol, not digestion. What is documented: acai's dark pigment can tint stool, and fresh, unprocessed pulp carries a specific regional food-safety issue that's worth knowing about, separate from the frozen, dried or capsule acai sold in the US.

Why acai might affect digestion, in theory

Acai pulp contains dietary fiber, like most whole fruit (USDA FoodData Central lists it among fruits with a meaningful fiber content per serving). Increasing fiber intake quickly — from any food, not just acai — can cause gas, bloating or looser stool in some people while the gut adjusts, and can have the opposite effect, easing constipation, in others. That's general digestive physiology, not a finding specific to acai; none of the published acai trials measured it directly, whether in whole pulp, juice or a capsule extract.

Why acai can change stool color

Acai's anthocyanins — the same pigments responsible for its deep purple-black color — can tint stool darker, or give it a reddish tinge, the same way beets, blueberries or dark grape juice can. That's a pigment passing through, not a digestive problem. Genuinely black, tarry stool that isn't explained by a pigmented food or a supplement like iron is a different matter, and can be a sign of bleeding higher in the digestive tract — that's worth a doctor's attention regardless of whether you've eaten acai recently.

A regional food-safety finding worth knowing

A 2026 epidemiological study looked at acute Chagas disease cases in Para state, Brazil, the Brazilian region that produces the most acai — and found the case count rises and falls with the acai harvest season, with 87% of cases transmitted orally. The likely route is contamination of fresh, unprocessed acai pulp with the parasite that causes the disease during local harvesting and handling, not the fruit itself. This is a documented issue tied to fresh pulp sold and consumed locally in that specific supply chain; it isn't something reported in frozen pulp, dried powder or capsule acai processed for the US market, which go through freezing, drying or extraction steps the local fresh product doesn't. It's a reason to be cautious about fresh, unprocessed acai specifically if you're ever in that region, not a concern tied to the forms sold here.

Questions people ask

Does acai make you poop?

No trial measured this directly. Acai pulp contains fiber, and fiber-rich foods can affect bowel movements in either direction depending on the person and how much is eaten, but that's general nutrition, not a specific, tested effect of acai.

Can acai cause gas or an upset stomach?

No published trial reports this as an outcome. As with any fiber-containing food introduced in a new amount, some people notice gas or bloating; that isn't documented as an acai-specific reaction.

Can acai turn your poop black, red or green?

Its anthocyanin pigment can tint stool darker or reddish, similar to other deeply colored foods. A green tinge is more often explained by other foods or supplements eaten around the same time than by acai specifically. Stool that's black and tarry, without an obvious pigmented food to explain it, is worth mentioning to a doctor.

Can acai cause parasites?

Fresh, unprocessed acai pulp handled locally in Brazil's Amazon region has been tied to Chagas disease transmission in published surveillance data — a documented regional food-safety issue in that specific supply chain, not something reported in the frozen, dried or capsule forms sold in the US.

Related reading: acai side effects, who should not take acai, and what is acai?