The post-mortem biochemical determination of hypoglycaemia in the prac
tice of forensic medicine is notoriously imprecise and attracts perenn
ial criticisms, particularly from those who may be alien to the peculi
arities of medical jurisprudence. There has been re-emphasis recently
on the neuropathological pathoclisis ascribed to prolonged hypoglycaem
ia. Unfortunately the value perceived is limited by pathognomonic unre
liability owing to agonal multifactorial influences and rapidly fatal
nocturnal hypoglycaemia. The predicament is oppressive to a considerat
ion of preponderant evidence and an unpopular diagnosis of perimortem
hypoglycaemia, unless audacious, may be precluded simply because the p
roof is difficult. This is likely to contribute to diagnostic under-es
timation of enigmatic diabetic deaths. A suspected case of lethal noct
urnal hypoglycaemia in a young diabetic on 'animal' insulin is present
ed to restore some perspective to the clinico-pathological deference f
or an endangered post-mortem diagnosis of hypoglycaemia inferred from
minimal evidence.