Amitriptyline, a tricyclic antidepressant (TCA), was effective in suppressing self-mutilation of a peripherally deafferented hind paw in rats ('autotomy'). This effect was not due to the drug's sedative effect, since locomotor activity was not lower in treated than untreated rats. Daily injections of normal saline also suppressed autotomy, but for a shorter period of time than amitriptyline. This effect was not apparent in diazepam-treated rats, suggesting that the saline injection delayed autotomy as a result of stress-induced anti-nociception. Since amitriptyline is effective in humans in alleviating certain chronic pain disorders, these results further corroborate the suggestion that autotomy is a model of chronic pain, sensitive to centrally acting analgesics and to some forms of stress.