I understand your concern. Watery diarrhoea in children are usually seen in viral diarrhoea and generally subsides. in 2-3 days. But lasting for 20 days points to some infection. But before concluding I would ask if there is fever and vomiting besides asking if the baby is fed from bottle. In that case stop bottle and feed only breast milk and other feeds, if you must from cup with spoon . I have seen this working in my clinic and I strongly dissuade bottle feed and would advise a probiotic powder and a racecadotril powder available in sachets like Zedott, Enuff or Racedot. YOu must give enough water and ORS after every loose motion to prevent dehydration which can be fatal.Hence my advice is to stop bottle feed and give a racecadotril preparation I have explained and you can reassess with your doctor. Regards