Against the background that what one eats affects the gastrointestinal tract (G.I T), the role of diet and dietary habits including fibres, food additives and preservatives on the aetiology of gastric cancers, colorectal cancers and other G.I disorders in the tropics are herein reviewed. Carcinomas of the gut believed to be on the decline in the developed countries have plateaued and increasing cases are being reported in the tropics. Africa and Nigeria in particular, with little or no cases previously are currently experiencing patterns of incidence similar to those of the Western Hemisphere. All these developments are premeditated by the nature of diets and dietary factors contained therein. Some of these factors contain chemical carcinogens, irritants as additives or preservatives, high cholesterol, highly spiced foods, alcohol, nicotine, xanthines, caffeine, most of which provoke gastric acid secretions dyspepsia and heartburn, and they lack vegetables and dietary fibres known to protect the G.I tract against various diseases. The roles of dietary hygiene implicating certain microorganisms associated with G.I diseases like Helicobacter Pylori
are also discussed. It presupposes that well articulated diet and proper dietary manipulations remain the cure for all diet induced G.I disorders while avoidance of such habits that predispose to them must be encouraged to ensure proper and healthy G.I.T.