hello i have gone through your query.The most common cause of loose motions is a virus called rotavirus.it can be due to a bacterial infection also. Diarrhoea in babies can also be caused by: formula feeds, if they are not properly diluted colds antibiotics allergies Look for these signs of dehydration in your infant Urinating less often than usual (fewer wet diapers) Irritability Dry mouth No tears when crying Unusual drowsiness or lethargy treatment includes: oral rehydration solution (ORS) or electrolyte solution breast feeding is the best option its a good sign that your baby is active but having diarrhea since one week is not good. presence of pus cells in stool suggest some infection i wud suggest you to visit a doctor hope this ans helps Regards Dr. Shesh