Although approved for use only in cervical dystonia, BTX-B (Myobloc, Elan Pharmaceticals) is reported to be used “off-label” for hyperhidrosis and facial wrinkles. There are no published reports on BTX-B in hyperhidrosis, but a case report of its use in a patient with palmar hyperhidrosis who did not respond to BTX-A is of interest. After 2 treatments with 100 U of Botox to each palm 3 months apart and little response, the patient was treated with 2500 U of BTX-B to each palm. He stopped having excessive palmar sweating, but 2 days after injection complained of blurred vision, indigestion, and dysphagia with a “dry sore throat.” The indigestion and dysphagia cleared within 10 days, but the blurred vision lasted for 3 weeks. Since BTX-B has been reported to cause dysphagia and a dry mouth when used at a dose of 5000 to 10000 U for cervical dystonia, this patient’s symptoms were thought to be due to the toxin. Further study of BTX-B with regard to both safety and efficacy in the treatment of hyperhidrosis is clearly needed.