Local anesthesia is an effective method to control pain. Neosaxitoxin is a phycotoxin whose molecular mechanism includes a reversible inhibition of voltage gated sodium channels at the axonal level, impeding nerve impulse propagation. The present study was designed to evaluate the clinical efficacy of Neosaxitoxin as a local long-acting pain blocker in horse bucked shins, and it was found to effectively control pain. While Neosaxitoxin and Gonyautoxin, another Paralytic Shellfish Poison (PSP) toxin, have been successfully used in humans as long-lasting pain blockers, this finding marks the first time a PSP has been shown to have an established effect in veterinary medicine. (C) 2017 Elsevier Ltd. All rights reserved.