Products, pharmaceutical compositions, methods of use, and kits are provided for treating a patient suffering from
botulinum neurotoxin intoxication. Featured are single-domain variable heavy-chain (VHH) polypeptides (antibodies) that target and neutralize the light chain (LC)
protease domains of
botulinum neurotoxin (BoNT), i.e., BoNT LC / A and BoNT LC / B, and that advantageously provide late and post-
exposure therapy for
botulism patients. The LC / A
toxin-binding and LC / B
toxin-binding VHH polypeptides, which can be recombinantly produced, specifically bind to the LCs of the botulinum neurotoxins to inhibit
toxin activity and treat intoxication.