SB 11.18.2
kanda-mula-phalair vanyair
medhyair vrttim prakalpayet
vasita valkalam vasas
trna-parnajinani va
Translation:
Having adopted the vanaprastha order of life, one should arrange one’s sustenance by eating uncontaminated bulbs, roots and fruits that grow in the forest. One may dress oneself with tree bark, grass, leaves or animal skins.
Purport:
A renounced sage in the forest does not kill animals, but rather acquires skins from animals who have suffered natural death. According to a passage from Manu-samhita, quoted by Srila Bhaktisiddhanta Sarasvati Thakura, the word medhyaih, or “pure,” indicates that while residing in the forest a sage may not accept honey-based liquors, animal flesh, fungus, mushrooms, horseradish or any hallucinogenic or intoxicating herbs, even those taken as so-called medicine.