What Leads To Black Stool When On Metronidazole Flagy And Doxycyclin?

Posted on Sat, 11 Jan 2014

Medically reviewed by Ask A Doctor - 24x7 Medical Review Team

Sat, 11 Jan 2014 Answered on

Thu, 30 Jan 2014 Last reviewed on

Question : Last month I had a colonscopy and endoscopy The results came back normal except I had 1 polyp that was benign.However the doctor said I have H polry. He gave me metronidazole flagy and doxycycline. I have been noticingmy stool is dark almost black . It seemed everthing was fine before I started to medication . Do I need to worry?

Answered by Dr. Amit Jain (2 hours later)

Brief Answer: Please see the details Detailed Answer: Hello! Thanks for putting your query in XXXXXXX I am a Gastroenterologist (DM). Black colored stool may be due to medicine bismuth subcalicyclate which you haven't mentioned which is given for eradication of H.pylori. So please check your medicines whether bismuth is there or not. If it is there then there is nothing to worry as it will disappear itself once it is stopped I hope I have answered your query and this will help you. If you have any further query I will be happy to answer that too. Remain in touch and get-well soon

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar