The extremely potent and selective nicotinic acetylcholine receptor antagonist methyllycaconitine, MLA, and related norditerpene alkaloids are finding increasing use as neurochemical probes and as targets for structure-activity relationship studies. In this work, an assay procedure for MLA which utilises ion suppression reverse-phase HPLC with UV absorbance detection at 270 nm is described. The method detected 280 ng MLA on column.