What is the reason for the foul smell of a child's stool?

Patient's question:

Detailed medical condition and consultation purpose: The stool has a relatively strong sour odor
Current general condition: Appetite and urination are normal, with bowel movements 3-4 times a day
Auxiliary tests:
Other: Drinking pediatric star tea. First question supplement: The child is breastfed

Doctor's answer:

Hello! The baby's stool has a sour odor, which may indicate indigestion. It could be due to excessive consumption of protein-rich foods. These proteins can neutralize stomach acid, reducing the acidity of gastric juice and hindering the complete digestion and absorption of proteins. Additionally, bacterial decomposition in the intestinal tract further contributes to the foul smell of the stool.
It is recommended to dilute the formula milk slightly. Breastfeeding mothers should eat more vegetables and fruits, drink plenty of water, consume appropriate amounts of meat, eggs, and fish, and reduce the intake of high-fat foods. This will ensure that breast milk is nutritionally balanced and easily digestible. Additionally, you can take Mamikai (a probiotic supplement).