Snake venoms, for example, are complex mixtures of enzymatic proteins and different toxins. Sometimes a combination of these effects is involved, however, and variations may occur within genera or even within species. The effects of insect stings are usually the result of histamines that produce local irritation and swelling. Serums against various venoms can be produced by injecting animals such as horses with sublethal doses and extracting the immune serum, or antivenin, that the animal body produces. Often poisonous creatures are harmless unless eaten.
Venomous creatures can often use their poison as a weapon.
Cobras are all venomous, yet most are not poisonous, so long as the venom glands are not eaten.