A quaternary ammonium ion comprising an anilinium ion core having three methyl substituents on the aniline nitrogen, and a 3-[(dimethylcarbamoyl)oxy] substituent at position 3. It is a parasympathomimetic which acts as a reversible acetylcholinesterase inhibitor. ChEBI: Neostigmine is a quaternary ammonium ion comprising an anilinium ion core having three methyl substituents on the aniline nitrogen, and a 3-[(dimethylcarbamoyl)oxy] substituent at position 3. It is a parasympathomimetic which acts as a reversible acetylcholinesterase inhibitor. It has a role as an EC 3.1.1.7 (acetylcholinesterase) inhibitor and an antidote to curare poisoning.