A novel type A botulinum toxin preparation isprovided. A neuromuscular transmission blocking agentcomprising as an active ingredient a highly purified type Abotulinum toxin from Clostridium botulinum as infantbotulism pathogen and a medicament for treating a diseasewith muscle overactivity comprising as an active ingredientsaid toxin. In particular, the medicament of the presentinvention, as compared to conventional known botulinumtoxin preparations, has rapid potential efficacy, is lessdiffusive and thus, has a broader safety margin, and may beused as therapeutic medicament for decreasing local muscleoveractivity in a disease with muscle overactivity.
