Does eating lettuce cause black stools?
Disease description:
A few days ago, a relative gave me a large amount of lettuce (oilseed lettuce). I ate it for three consecutive days, and today I noticed my stool was darker in color when using the restroom. Can eating oilseed lettuce cause black stools?
Doctor's answer (1)
Dr. Shen Yonghua
Eating lettuce (Lactuca sativa var. angustana) may cause black stools. This occurs because stools naturally contain a significant amount of iron; in some individuals, the chlorophyll in green leafy vegetables is absorbed and subsequently reacts with intestinal iron or other substances, leading to darkened stools. However, this effect does not occur in everyone and is entirely benign—no treatment is required. Additionally, black stools may also result from certain medications or underlying gastrointestinal disorders.
