The causes of two-month-old baby mouth froth mainly include the following: 1, caused by children at play, if parents do not accompany timely, children tend to play on their own, thus manifesting themselves as spitting foam, this time the baby is often in a better mood, and will also make babbling sounds. 2, caused by children suffering from pneumonia, children suffering from pneumonia will often appear after the number of breathing significantly accelerated, children will also have the trigeminal sign, this time faster breathing often causes the mouth saliva is not swallowed in time to the digestive tract. The child will also have the triple concave sign, this time breathing faster, often causing the saliva in the mouth is not swallowed in time to the digestive tract, and then the performance of the mouth spitting foam.