Aitareyabrahmana 7.30

7.30

‘These indeed are the three draughts, O king,’ he said,
‘for which a kṣatriya sacrificer should not entertain any hope.
Now this is his own draught:
he should press the descending aerial roots of the nyagrodha tree and the fruits of the udumbara, aśvattha, and plakṣa,
and drink them. That is his own draught.
For when the gods, having sacrificed with the sacrifice, went to the heavenly world,
they overturned those cups there, and they became nyagrodha trees.
Even now they call them “the overturned ones” in Kurukṣetra.
Those were the first-born of the nyagrodha trees, and others were born from them.
Because they grew downwards (nyañcaḥ), therefore it grows downwards (nyaṅ rohati): its name is indeed nyagroha.
Being nyagroha, they call it nyagrodha cryptically,
for the gods are fond of the cryptic, as it were.’