1. Four unfavorable experiences with the use of the Ayre rotating stomach brush are reported. In one case, a piece of gastric mucosa was accidentally obtained; in 2 others, serious trauma to the posterior wall in the stomach occurred, and in a fourth, the brush unit became detached in the stomach.
2. Mechanisms involved in these accidents and methods of prevention are discussed. In particular, (a) the brush should not be pushed through the cardia if resistance is met; (b) amyloidosis, leukemia, or other hemorrhagic disorders are contraindications to the use of the instrument; (c) anticoagulation therapy may be dangerous in the immediate period after cytologic abrasion is performed; and (d) the brush should not be used to break up gastric bezoars.