CARCINOMA of the human stomach is generally associated with hypochlorhydria or achlorhydria. This experimental study was designed to determine whether artificially induced hypochlorhydria, by vagotomy and gastroenterostomy, would enhance the effect of known carcinogens in the stomach of an experimental animal. Methods The experimental animal was the rat (Wistar-derived strain). The method of carcinogenesis was the implantation of 20-methyl cholanthrene (20-MC)-impregnated cotton threads into the anterior wall of the glandular stomach (Fig 1). This method yields a reproducible incidence of tumor induction of approximately 45% as shown in this and other laboratories.1 Young adult rats of both sexes, weighing approximately 150 gm, were divided into three groups: Group 1 (Control). —Implanted into the glandular portion of the intact stomach, near the most dependent part of the greater curvature were 20-MC threads. Group 2. —An anterior gastrojejunostomy measuring 6 mm was made near the most dependent portion of the glandular