Charak Samhita
स्रोतःसु तक्रशुद्धेषु रसः सम्यगुपैति यः। तेन पुष्टिर्बलं वर्णः प्रहर्षश्चोपजायते॥८७॥
Butter-milk cleanses the channels of circulation as a result of which rasa (end product of the food after digestion) reaches ॥ the tissue elements॥ appropriately. This produces proper nourishment, strength, complexion
english translation
srotaHsu takrazuddheSu rasaH samyagupaiti yaH। tena puSTirbalaM varNaH praharSazcopajAyate॥87॥
hk transliteration by Sanscript