Some babies lose weight physiologically, that is, there is not necessarily any problem. The 6-month-old baby is in the stage of adding complementary food. From 0 to 6 months, the baby takes breast milk or breast milk substitutes as the staple food, but after 6 months, it gradually changes to solid food as the staple food. You can see if the baby's complementary food is not enough or the ingredients are wrong. It must be from thin to dry, from simple to complex, from single to diverse. This stage is very important to exercise the baby's digestive function.