Endoscopic transthoracic sympathicotomy, otherwise an established treatment for palmar hyperhidrosis, was used to treat patients troubled by facial blushing, one of the commonest symptoms of social phobia. The results were evaluated by means of a questionnaire answered by 90 per cent (219/244) of the patients, who rated their symptoms on a visual analogue scale (0-10) after a mean follow-up of eight months. According to the ratings, blushing was significantly reduced from a mean (+/- SEM) of 8.7 +/- 0.1 to 2.2 +/- 0.2 (p < 0.0001). Of the series as a whole, 85 per cent declared themselves satisfied with the outcome.