DS, 17 months, has had funny poo for about 9 days now. It's quite loose and very smelly (sour) and varies in colour from very dark to very yellow. He is also going very very frequently so that he is now getting a sore bum despite us changing him asap plus waking in the night to poo which he has never done since a newborn. He is fine in himself, alert and drinking normally though has also gone off his food a bit in the last few days. Something is definitely up but not sure what. He has the single measles jab on 18th Aug so could possibly be a delayed reaction to that? Spoke to dr last week who said it was unlikely to be food poisoning as he's not being sick but to bring in a sample if it doesn't clear up, which I will do tomorrow. Does anyone have any ideas what this could be? Worried it is more than a stomach upset as it's taking so long to go. Will see dr in next few days but any thoughts before then would be very welcome.