Trypsin fails as Australian snake bite cure.

Trypsin has been claimed a new and effective treatment for venomous snake bite. We found that significant inactivation of snake venom lethal potency occurred in vitro when trypsin was incubated with venom and subsequently injected into mice. Premixing of tiger snake venom (TSV) and trypsin just before injection did not significantly increase the survival rate of mice over that of controls injected with TSV alone. Trypsin injected 10 to 30 minutes after TSV injection did not increase the survival rate of mice compared with controls. Specific antivenom was effective as an antidote when there was a 10 minute delay after venom injection. There was varying susceptibility of different venoms to trypsin inactivation in vivo.