Srimad-Bhagavatam: Canto 8 - Chapter 1 - Verse 22-23

Sanskrit:

क्षिप्‍त्वा क्षीरोदधौ सर्वा वीरुत्तृणलतौषधी: ।मन्थानं मन्दरं कृत्वा नेत्रं कृत्वा तु वासुकिम् ॥ २२ ॥सहायेन मया देवा निर्मन्थध्वमतन्द्रिता: ।क्लेशभाजो भविष्यन्ति दैत्या यूयं फलग्रहा: ॥ २३ ॥

ITRANS:

kṣiptvā kṣīrodadhau sarvāvīrut-tṛṇa-latauṣadhīḥmanthānaṁ mandaraṁ kṛtvānetraṁ kṛtvā tu vāsukim

Translation:

O demigods, cast into the Ocean of Milk all kinds of vegetables, grass, creepers and drugs. Then, with My help, making Mandara Mountain the churning rod and Vāsuki the rope for churning, churn the Ocean of Milk with undiverted attention. Thus the demons will be engaged in labor, but you, the demigods, will gain the actual result, the nectar produced from the ocean.

Purport:

It appears that when different kinds of drugs, creepers, grass and vegetables are put into this milk and the milk is churned, as milk is churned for butter, the active principles of the vegetables and drugs mix with the milk, and the result is nectar.