Surreptitious laxative abuse: keep it in mind.

The clinical example is one of diarrhea induced by the surreptitious use of laxatives. A 45-year-old man had a 3-year history of diarrhea, which had been fully investigated, without a cause having been identified. His general health appeared to be affected little, but he had the clinical features of an associated depressive illness. The diagnosis of laxative abuse was supported by the finding of abnormally high concentrations of magnesium in fecal water. He admitted initially, and later denied, the surreptitious ingestion of laxatives. This example is discussed with regard to features that were typical and atypical of the syndrome of laxative abuse. The significant points to be appreciated are 1) that any chronic, watery diarrhea that has eluded diagnosis after an adequate investigation is possibly self-induced, and 2) that awareness of this syndrome and its prevalence in selected cohorts can lead to direct and inexpensive documentation of the diagnosis.