Your child is suffering from gastro-enteritis (GE). Most GE in children is of viral etiology and is self limiting. Antibiotics are needed only if cholera or dysentery is suspected. Neither appears to be the case in your child. Therefore, antibiotics and metrogyl are not likely to be of much benefit. What is more important is that adequate amounts of fluids are given to prevent dehydration. As a rough guide, give about 50 ml of ORS /loose stool if your child weighs around 10 kg. If the child accepts well orally and is passing urine 4-5 times per day, his hydration is normal. Continue feeding him the usual foods and milk. Remember that during sickness a child's appetite decreases. So, don't force feed, only offer more liquids: soup, neembu-paani etc and solids if he is willing to take. Typically GE would last for 3-4 days only.