Why snake don't die of its own poison and why you eat snake and still do not die?
Snake poison is a special protein which is made of enzymes and other things. Snake poison is made in special organ which do not let venom pass into body blood. So, snake do not die of its own poison.
Also, because snake poison is made of special protein and it is not a type of chemical, our digestive system can break it down when it goes into our body through digestive tract. Only if Snake venom goes directly in blood stream then we can die of Snake venom.
Detail answer: Can snakes die from their own venom?