This deals with toxicity of Central Nervous System (CNS), affecting the brain and destructs the Nerve tissues. Cases of this substances include Conotoxin, Chlorotoxin, Tetrodotoxin, causes neuro-toxicity & directly affecting the brain and related functions. Neurotoxicity may also occur due to some drug therapies, organ transplant or exposures to significant metal. Many billions of dollars spend each year voluntarily for purchasing chemicals like caffeine, alcohol, and nicotine to influence the nervous system.