It is not needed for a long period as the intestinal bacteria will grow back naturally if you start eating healthy food (freshly prepared homemade food - if possible use organic /natural food ). It takes consistency in following a healthy lifestyle. About intestinal bacteria, and how healthy food habits and routine lifestyle changes can help overcome digestive problems.
Why to worry about 2 to 3 times per day watery motion?
Loose stools or diarrhoea in a simple language means to change in frequency and consistency of your son’s stool frequency and consistency than routine. First, our worry should be only not to lose too much water from our child so ensure first adequate hydration don’t jump to medicines if not required really.
Second, he is 8 months and if is he breast feeding than beat to ensure good enough breastfeeding first. And if possible than give light complementary diet like khichadi/rice with curd. Don’t worry about smell if your son has no other symptoms. Consult doctor if you find less urine frequency, vomiting which reduce oral intake and other symptoms like fever, blood or mucus in stool. Thanks.