Neosaxitoxin (also known as NeoSTX, neosaxitoxina, (3aS,4R,10aS)-2-amino-4-(((aminocarbonyl)oxy)methyl)-3a,4,5,6,8,9-hexahydro-5-hydroxy-6-imino-1H,10H-pyrrolo(1,2-c)purine-10,10-diol, [(3aS,4R,10aS)-2-amino-5,10,10-trihydroxy-6-imino-3a,4,5,6,9,10-hexahydro-3H,8H-pyrrolo[1,2-c]purin-4-yl]methyl carbamate, [(3aS,4R,10aS)-5,10,10-Trihydroxy-2,6-diiminooctahydro-1H,8H-pyrrolo[1,2-c]purin-4-yl]methyl carbamate, 1H,10H-Pyrrolo(1,2-c)purine-10,10-diol, 2-amino-4-(((aminocarbonyl)oxy)methyl)-3a,4,5,6,8,9-hexahydro-5-hydroxy-6-imino-, (3aS,4R,10aS)-, 1H,10h-pyrrolo(1,2-c)purine-10,10-diol, 2-amino-4-(((aminocarbonyl)oxy)methyl)-3a,4,5,6,8,9-hexahydro-5-hydroxy-6-imino-, (3as-(3aα,4α,10ar*))-, 1H,10H-Pyrrolo(1,2-c)purine-10,10-diol, 2-amino-4-((aminocarbonyl)oxy)methyl-3a,4,5,6,8,9-hexahydro-5-hydroxy-6-imino-, (3aS,4R,10aS)-, 1H,10H-Pyrrolo(1,2-c)purine-10,10-diol, 2-amino-4-((aminocarbonyl)oxy)methyl-3a,4,5,6,8,9-hexahydro-5-hydroxy-6-imino-, (3aS-(3aα,4α,10aR*))- or neo-STX) is a neurotoxin substance of the amino acid class.