"If you ever do vomit 'coffee grounds' and you don't have a good cause for knowing where the blood is coming from - like you've swallowed blood from a nose bleed etc. - call for one of Tom's taxis ASAP." Oooh, I had that about ten years ago from a serious head injury, I fell downstairs and was bleeding from one ear, broken wrist and far too concussed to even think about big white taxis, and I recovered okay in the end - but I always wondered what it was?