Butyrylcholine chloride is primarily used in biochemical research as a substrate for studying the activity of cholinesterase enzymes, particularly butyrylcholinesterase. It helps in understanding enzyme kinetics and inhibition, which is crucial for developing treatments for conditions like Alzheimer's disease, where cholinesterase activity is a key focus. Additionally, it is employed in laboratory settings to differentiate between acetylcholinesterase and butyrylcholinesterase, aiding in the characterization of these enzymes. Its role in research contributes to advancements in neuropharmacology and toxicology.