Imidacloprid [1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine, CAS 138261-41-3] belongs to a relatively new class of insecticidal chemistry, the chloronicotinyl neonicotinoid compounds. Animal studies indicate relatively low toxicity to mammals. Despite wide usage in some countries, the understanding of human poisoning is quite limited. Here we report a fatal case of rapid ingestion of an insecticide formulation containing imidacloprid. Clinical manifestation included severe vomiting, hypertension, tachycardia, mydriasis with sluggish reaction to light, and loss of consciousness.