Glyphosate molecule, illustration. Glyphosate (C3.H8.N.O5.P) is a broad-spectrum herbicide and crop desiccant. It is used to kill weeds by inhibiting a plant enzyme that is involved in the synthesis of several aromatic amino acids. It has been classified as a probable carcinogen (cancer-causing chemical) in humans. The molecule's atoms are represented as colour-coded sphere: carbon (grey), hydrogen (white), oxygen (red), nitrogen (blue) and phosphorus (yellow).