You should worry about black stool when it has certain characteristics or is accompanied by other symptoms that suggest internal bleeding or a serious condition. Specifically, black stool that is tarry, sticky, has a strong foul odor, or looks like coffee grounds may indicate melena, which is caused by bleeding in the upper digestive tract, such as the esophagus, stomach, or small intestine. Additionally, if black stool persists for more than a couple of days, or is associated with symptoms like stomach pain, dizziness, vomiting blood, weakness, lightheadedness, or changes in bowel habits, it is important to seek medical attention promptly. Black stool caused by foods like black licorice, blueberries, or medications such as iron supplements is usually harmless and temporary if these other symptoms are absent. In summary, concerns arise if black stool:
- Is tarry, sticky, foul-smelling, or resembles coffee grounds
- Persists beyond a few bowel movements
- Is accompanied by symptoms such as abdominal pain, dizziness, vomiting blood, or weakness
- Occurs in people at high risk for gastrointestinal bleeding or with a history of related conditions
Immediate evaluation by a healthcare provider is recommended in these cases to rule out serious issues like ulcers, internal bleeding, or cancer.
