Hmmmmmm, thanks girls. She hasn't had any banana at all. The Farex she hasn't had for AGES (because she hates the stuff). She has been sick for about 3 weeks and seems to FINALLY be kicking it (touch wood!) and has had demazin, panadol and neurophen for it. The poo happened about 24hrs after her last dose of any of those meds. She is otherwise well - although possibly teething. About 10 minutes after the black poo she did another poo which was her normal green and mustard colour.
The poo in question only had intermittent thick strips of black which was very dark - not what I would expect for dried blood. I guess I will just watch the next few and see what happens... maybe it was a once off...

Thanks again girls!

MG