SB 8.6.22-23

kṣiptvā kṣīrodadhau sarvā
 vīrut-tṛṇa-latauṣadhīḥ
manthānaṁ mandaraṁ kṛtvā
 netraṁ kṛtvā tu vāsukim
sahāyena mayā devā
 nirmanthadhvam atandritāḥ
kleśa-bhājo bhaviṣyanti
 daityā yūyaṁ phala-grahāḥ
Word for word: 
kṣiptvā — putting; kṣīra-udadhau — in the Ocean of Milk; sarvāḥ — all kinds of; vīrut — creepers; tṛṇa — grass; latā — vegetables; auṣadhīḥ — and drugs; manthānam — the churning rod; mandaram — Mandara Mountain; kṛtvā — making; netram — the churning rope; kṛtvā — making; tu — but; vāsukim — the snake Vāsuki; sahāyena — with a helper; mayā — by Me; devāḥ — all the demigods; nirmanthadhvam — go on churning; atandritāḥ — very carefully, without diversion; kleśa-bhājaḥ — sharetakers of sufferings; bhaviṣyanti — will be; daityāḥ — the demons; yūyam — but all of you; phala-grahāḥ — gainers of the actual result.
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.