The information provided here is not a replacement for a doctor. You shouldn't use it for the purpose of self-diagnosing or self-medicating but rather so you can have a more informed discussion with a professional TCM practitioner.
In Chinese Medicine infantile malnutrition can be treated by one herbs that we have on record. Here is the list below.
Tamarind fruits might help with infantile malnutrition
Why might Tamarind Fruit (Suan Jiao) help with infantile malnutrition?
Because it is a herb specifically indicated to treat infantile malnutrition as can be seen on Tamarind Fruit's page.
Tamarind Fruits is a Cool herb that tastes Sour and Sweet. It targets the Stomach and the Heart.
Its main actions are: Clears Summer Heat and relieves Stomach food Stagnation.