The Sūtra of Golden Light 17.8

Suvarṇaprabhāsottamasūtra 17.8

tatraiva vaidyasya catuḥ prakāraṃ trimāsaparvāntare ṣaḍṛtūni /
ṣaḍdhātukauśalyaprajānitavyaṃ yathākramaṃ bhojanamauṣadhaṃ ca //