Why does eating red-fleshed dragon fruit make your poop red?

The reason why eating red-fleshed dragon fruit causes red-colored stool generally includes physiological and pathological factors.

1. Physiological factors

Red-fleshed dragon fruit usually contains abundant betacyanin, a water-soluble alkaloid pigment. When a large amount of dragon fruit is consumed, some of the betacyanin is absorbed by the small intestine into the bloodstream and then excreted through metabolism. The remaining portion of betacyanin, along with dietary fiber, cannot be fully absorbed and passes into the large intestine, resulting in red-colored stool. This is a normal physiological phenomenon.

2. Pathological factors

If red-colored stool occurs after eating red-fleshed dragon fruit and the color is particularly dark, it may indicate an underlying gastrointestinal bleeding condition, such as duodenal ulcer. In severe cases, the disease can damage or even rupture blood vessels beneath the mucosal lining. Combined with the betacyanin from the dragon fruit, this may lead to the aforementioned symptom. Additionally, symptoms such as recurrent abdominal pain may also be present.