I have done a hysteroscopy and fitting of Merina coil a week ago, and have a pelvic and urinary tract infection. In the last few days when I have been perscribed with Metronidozole and Augmentine by my GP and I have had very black stool. I generally feel better after the antibiotics but I am concerned, I have seen the gynaecologist who performed the surgery today yet she puts it down to medication. I do not have abdominal pain, apart from a lower back pain and feeling of bloating.