Netch Poison is a poison that does 5 points of damage to health and stamina for 4 seconds. It cannot be obtained without console commands. It is virtually the exact same as Frostbite Venom in terms of effects and model and only differs in name and ID.
Netch poison can only be obtained through the use of the Console command:
player.additem 01cd7d X, whereas X is the desired quantity.