snake venom viper venom cerastes venom viperotoxin egyptian sand viper venom UBERON:0013112 Venoms from snakes of the viperid family. They tend to be less toxic than elapid or hydrophid venoms and act mainly on the vascular system, interfering with coagulation and capillary membrane integrity and are highly cytotoxic. They contain large amounts of several enzymes, other factors, and some toxins. viper venom MESH:D014757