Snake venom comes in different types. Different types of venom have different effects on humans. Cytotoxic Venom destroys tissue and causes pain, swelling and eats away at the flesh. Cytotoxic bites vary in potency according to the species of snake, size of the snake and the amount of venom injected. Snakes with cytotoxic venom include most of the Adders and Vipers, some Cobra species such as the Mozambique Spitting Cobra, Black Necked Spitting Cobra and Zebra Cobra. Species whose venom is cytotoxic and can cause death include Rattle Snakes, Puff Adders, Gaboon Vipers, Saw Scaled Vipers, Russell’s Viper, Bush Master, Lance Head Vipers and many other viper species as well as the Cobra species listed above. A bite from one of these snakes will cause severe swelling and often the entire limb will swell up. Tissue damage will occur and without antivenom death may follow. There are species of Viper whose venom does not cause such severe symptoms and antivenom is not usually needed and is often not produced as the symptoms of the bite are not severe enough to warrant the time and money it takes to produce antivenom. These species include Horned Adders, Copper Heads, Night Adders, White Lipped Tree Vipers and Common Adders. Neurotoxic Venom is very dangerous and bites will cause drowsiness, blurred vision, difficulty speaking and eventually paralysis which causes your lungs to stop working. Neurotoxic venom is very fast acting. If you get bitten antivenom will usually be needed, patients may also have to be put on life support if antivenom is not available or if they are not treated quick enough. Snakes which have neurotoxic venom include: Almost all of the Cobras, Mambas, Coral Snakes, Banded Kraits and Yellow Bellied Sea Snakes. Heamotoxic venom stops blood from clotting causing internal bleeding. The bite site will start bleeding and the person will start to bleed from small cuts and mucus membranes. The person will also have headaches, nausea and may start to vomit. Death may occur if antivenom is not administered. Snakes which have heamotoxic venom include: the Boomslang , Vine Snakes, Saw Scaled Vipers and African Bush Vipers. Some snakes have a combination of different venom types for example the Berg Adder.