Atropine (Standard) is the standard substance of Atropine, and it is applicable for quantitative analysis, quality control, and related research in biochemical experiments. Atropine (DL-Hyoscyamine) Sulfate is the sulfate salt of atropine, a naturally-occurring alkaloid isolated from the plant Atropa belladonna. Atropine functions as a sympathetic, competitive antagonist of muscarinic cholinergic receptors, thereby abolishing the effects of parasympathetic stimulation.