<s>[INST] hi i am looking after my 9 month old grandson and he has just done his 24 hours with just water (he got up yesterday morning with sickness and diarrhea) i know he must have dried toast for his first meal but how long till he can go back onto his milk? [/INST] Dear user first I would like to tell you that diarrhea is very common problem in infants, and you need not worry about that, but you should do simple steps.......allergy to certain milk formula that baby take, and then you discuss with your doctor to change milk formula and if not, so his milk can be given at any time diarrhea may have more than one cause, but the most common cause in that age 9 months is viral infection of the intestine ....viral infection causes severe watery diarrhea and may lead to complication as deny Chat Doctor. ..... you should give your grandson oral rely </s>