My husband told me this week that when he went to the toilet, his stools were black. (TMI, I know). He didn't realise the potential significance of this, but of course I did. I asked him to be vigilant and tell me if it happened again. Then It struck me that he had started on Vitamin B 12 injections a couple of days before. I of course resorted to the Internet, and found that, yes, this often happened with this treatment. I had to hand the prescription in to the chemist for them to send med to the surgery, so I never saw the package at all. If I had, I probably would have read the relevant information in the beginning.