Taking metronidazole will not make the stool black under normal circumstances.
Black stool may be because of eating black food during the medication, or the existence of peptic ulcer, after eating metronidazole on the gastrointestinal mucosa to produce stimulation, causing bleeding ulcers will appear the symptoms of black stool. If there is a peptic ulcer, esophagogastric fundus varices, acute hemorrhagic gastritis and other causes of gastrointestinal bleeding, after may also cause black stool.
Metronidazole is a kind of antibiotic against anaerobic bacteria, after eating will be completely absorbed by the body, generally and will not affect the habit of defecation, will not lead to changes in the color of the stool, so after eating metronidazole under normal circumstances the stool is not black.
If you eat metronidazole after the black stool, may be because during this period to eat animal blood, black sesame, black rice and other foods containing more melanin, will cause the black stool, which will not be accompanied by abdominal discomfort.
If you have a peptic ulcer, eating metronidazole will irritate the gastrointestinal mucosa and cause the ulcer to bleed, and then you will have black stools. If there is a peptic ulcer, esophagogastric fundus varices, acute hemorrhagic gastritis and other causes of gastrointestinal bleeding, after the black stool may also cause
If the phenomenon of black stools exists, it is recommended to go to the hospital as soon as possible, and give relevant measures with the help of doctors.