Any idea why my 17 year old should be doing black poo? He has had IBS in the past and felt IBS-ish last week. No diarrhoea, but black poo (looks more dark red really) and windy tummy. Took him to the doc, doc concerned and ordered blood tests. His haemoglobin is low, which also implies he's bleeding from somewhere inside and I'm freaking out. The doc has requested another blood test to see if haemoglobin levels are falling or stable and then I guess he'll probably have to have some more tests, like endoscopy. The doc said black poo means old blood which can mean it's from the upper GI - my son doesn't drink alcohol, doesn't take aspirin, hasn't eaten any foods with food colouring in or taken any vitamins with iron in and obviously is bleeding cos of the low haemoglobin - so what could it be? I'm thinking all sorts of horrible cancer thoughts at the moment and I'm really worried. It doesn't help that my son has autism, so life is pretty stressful for him at the best of times. We have blood test again on Thursday and new doc appt on Monday for the results of the other blood tests and decision on what happens next.