Giardia lamblia in patients undergoing upper G.I. endoscopy.

To determine the frequency of giardiasis in patients undergoing upper G.I. endoscopy for dyspepsia and other upper G.I. disorders, duodenal aspirates were collected in 200 patients and simultaneous duodenal biopsies in 163 patients. Nine percent aspirates and 1.8% duodenal biopsies showed Giardia lamblia trophozoites. Giardia as a cause of dyspepsia should be considered in patients with negative endoscopy and in those who remain symptomatic inspite of adequate treatment for known upper G.I. disorders.