In Europe, the common adder ( Vipera berus ) is extensively distributed and causes more bites than any other species in the genus Vipera.1 In Hungary, there are two subspecies; the nominate form ( V. b. berus ) in the East and Northeast and the Bosnian adder ( V. b. bosniensis ) in the Southwest (Figures 1 and 2).2 Figure 1. Common adders ( Vipera berus ) from Hungary: ( a and b ) V. b. berus , female specimens from the population where our patient was bitten (Vamosatya, Szabolcs–Szatmar–Bereg County, E Hungary) (Photographs Tamas Malina). ( c ) V. b. bosniensis female from Darvaspuszta, Somogy County, SW Hungary (Photographs Zoltan Korsos). Envenomings by V. berus result in characteristic systemic symptoms including early ‘anaphylactic’ features such as tachycardia, dizziness, hypotension, shock and gastrointestinal symptoms, coagulopathy and neutrophil leucocytosis.1,3,4 These symptoms resemble those caused by V. aspis , reflecting the similarities in the composition of their venoms.5 Systemic neurotoxicity has been described in patients envenomed by certain populations of some subspecies of V. aspis and V. ammodytes in Europe.6 It has been attributed to pre-synaptic (ammodytoxins) or post-synaptic neurotoxic phospholipases A2 (PLA2) in their venoms.6 However, neurotoxicity is a most unusual and unexpected clinical feature of V. berus envenoming. We describe here a case from eastern Hungary with other interesting features and review the scanty and somewhat obscure literature on this phenomenon. ### Case report A previously healthy 27-year-old man was bitten by an adult female V. berus 70–72 cm in total length on 23 April 2007 in Szabolcs–Szatmar–Bereg County in eastern Hungary (Figure 2). The snake was captured alive and expertly identified. The victim reported no previous snakebites. Two fangs impaled the left thumb, causing burning pain that became throbbing in quality. The bitten finger swelled immediately and a small haematoma formed at the …