At present, the majority of cases of blepharospasm are treated by injection of preparations containing botulinum neurotoxin. However, there are a range of other potential options, including drugs taken orally, physical treatments, topical medications, and surgery. Alongside these measures, it is essential to educate patients about the condition, avoid prescription of agents which may provoke dystonia (such as dopamine antagonists), ensure trauma does not occur to the cornea or eye generally, and provide general support. The toxin which possesses the most potency in human subjects is botulinum neurotoxin (BoNT), which is synthesised by the bacterial organism, Clostridium botulinum. This toxin results in muscles becoming paralysed at the muscle end-plate. The affected muscle lacks tone and has absent reflexes. The toxin occurs in seven forms, which can be distinguished on serological grounds and are labelled A to G. Serotypes A and B are marketed for clinical use. The seven serotypes all share a similar molecular mass of 150 kDa and consist of a heavy and light chain, which are bonded to each other by a disulphide linkage. The light chain is the toxic component, whereas the heavy chain interacts with a cellular receptor prior to the entire toxin being endocytosed.