Ashtangasamgraha 2.2

2.2

gurubhakto 'bhiyukto 'tiyukto dhīsmṛtipāṭavaiḥ |

ṛjvāsyanāsānayanastanusnigdhanakhacchaviḥ ||

tvakṣu tilvakaḥ |

kṣīreṣu snuhī |

phaleṣu harītakī pradhānāni |

trivṛtāyāḥ khalu dvividhaṃ mūlamaruṇaṃ śyāvaṃ ca |

tatrāruṇaṃ kaṣāyamadhuraṃ vipāke kaṭukaṃ rūkṣaṃ śleṣmapittaharaṃ kalpanāṃviśeṣāt punaḥ sarvavyādhipraśamanam |

sukhavirecanatvāt śiśusthavirasukumāramṛdukoṣṭheṣu praśastaṃ trivṛcchabdavācyaṃ ca ||

annādasya hitamannam |

ubhayavṛtterubhayam ||

Devoted to his teacher, diligent, highly endowed with the sharp faculties of intellect and memory, / having a straight mouth, nose, and eyes, and a thin, glossy luster of nails;

among barks, tilvaka;
among milks, snuhī;
among fruits, harītakī are foremost.

Trivṛt indeed has a two-fold root: reddish and blackish.
There, the reddish one is astringent-sweet, pungent in post-digestive effect, dry, alleviates śleṣman and pitta, and, due to distinct processing, further pacifies all diseases.
Because it purges gently, it is recommended for children, the elderly, delicate persons, and those of soft bowels; and it is denoted by the word 'trivṛt'.

For an eater of food, food is wholesome;
for one accustomed to both, both.