The venom of scorpion and spider contain numerous neurotoxic compounds like proteins, peptides, and polyamine blocking to the glutamatergic neuromuscular transmission or acting on various types of ion channels. Such biological active compounds in the venom grand are used for offensive or defensive purposes to paralyze or prey on other insects. This diversity of compounds and actions provide a wealth of bioactive compounds that is a resource of neuroscience research and a source of novel pharmaceuticals. Among these studies mass spectrometry is used as one of the unique characterization method for such venom from the insect.