Chiral phonons are concerted mirror-symmetric movements of atomic groups connected by covalent and intermolecular bonds. Finding chiral phonons in biocrystals is fundamentally and technologically important because these lattice vibrations should be highly specific to their short- and long-range organizations. Based on theoretical and experimental data they might be expected but not identified or utilized. Here we show that terahertz chiroptical spectroscopy enables registration and attribution of chiral phonons in microcrystals of numerous amino acids and dipeptides. Theoretical analysis and computer simulations confirm that sharp mirror-symmetric bands observed for left and right enantiomers originate from collective vibrations of biomolecules interconnected by hydrogen bonds into helical chains. Structure-property relationships for strong phonons with rotatory components in biocrystals were also identified. Bladder stones and health supplements display strong spectral signatures of chiral phonons indicating their immediate importance for biomedicine.