Naevus anaemicus, characterised by a hypopigmented macule, represents a cutaneous developmental anomaly based on functional abnormality of the cutaneous vessels unassociated with structural involvement. The pallor of the lesions was suspected to be due to either sympathetic hypertonia or a defect of nervous pathway or a defect at the neuroeffector junction. The present experimental study of 7 male patients was comprised of observations on cutaneous vascular reactions in response to chemical, mechanical and thermal stimuli. The cumulative results lent additional support to the postulation of a defect at the neuro effector junction.