Gustatory sweating is an autonomic disorder that frequently occurs after parotid gland surgery. We investigated the action of intracutaneous injections of botulinum toxin (BTX) (1.0-2.0 mouse units/2.25-cm2 skin area) in 45 patients (mean age, 52 years) with gustatory sweating. The area of hyperhidrosis was determined by Minor's iodine test before and up to 24 weeks after the injection. The effect of BTX was assessed by measuring the hyperhidrotic area. The maximum BTX-induced reduction of gustatory sweating was seen at 7.4 +/- 4.5 days after injection. The area of sweating decreased from 17.6 +/- 8.6 cm2 before BTX to 1.3 +/- 1.6 cm2 after BTX (p < 0.0001). Half the patients rated gustatory sweating subjectively as completely abolished, and the remainder felt pronounced improvement. No toxic effects were observed. In none of the patients did hyperhidrosis recur over a 6-month follow-up. We conclude that BTX is a safe and effective treatment that can be recommended as the therapy of choice in gustatory sweating.