Anthraquinone containing laxatives have been accused to cause degenerative changes in the colonic nerve tissue; prospective studies, however, are not available. This article reports the result of a semiprolective study in 11 matched pairs of chronically constipated women. Each pair consisted of one women having regularly taken an anthraquinone containing laxative for at least one year and a control person without such a medication. Six endoscopic biopsies were taken from the left colon and rectum which were evaluated by electron microscopy and subsequent ultramorphometry for the ratio of damaged to intact neurons, density of neurosecretory vesicles, axonal diameter and number of lysosomes. Medians of the three colonic locations were calculated in each individual and for each variable, and they were compared by non-parametric statistics. Medians of the ratio of damaged to intact neurons in anthraquinone treated women and controls were 0.162 and 0.146 (p = 0.0326, one-tail), medians of the number of type I vesicles were 293 and 348.5 per 100 microns 2 (p = 0.0365, one-tail), respectively. None of the other variables were different between groups. These data do not support the hypothesis that anthraquinone containing laxatives are able to provoke relevant degenerative changes in the colonic nerve tissue since the variables are either similar in both groups or only slight differences could be found which are unlikely to be of pathophysiological relevance.