Assessment of the entire surface of the mucosa of the diagnosed area is one of the key factors for high quality endoscopy. This is not obtainable without special preparation for endoscopy. Nationwide educational actions dedicated to informing patients how to prepare the bowel for colonoscopy have resulted in increased rate of detected pathological structures, clinically silent precancerous lesions in particular. Special pharmacological products for adequate colon preparation are available. Endoscopists are required to assess how well the colon was prepared for the procedure and include this information in their endoscopy report. The results of such efforts are already demonstrated by the decrease in the rate of colon cancer incidence and, most importantly, mortality. However, a similar effort is lacking as regards adequate preparation for gastroscopy despite it being the most common endoscopic examination. Generally, the required preparation for upper digestive tract endoscopy is limited to fasting for four to six hours before the procedure. Assessment of mucosa visibility is not required as an integral part of the gastroscopy report. This may be the reason for the low rate of early detection of gastric cancer and the high incidence of interval gastric cancer. Detection of advanced cancer results in low 5-year survival rates, with treatment mostly relying on extensive surgery. There are many publications available on premedication with simple mucolytic and anti-foaming agents for the detection of early precancerous lesions in the stomach, the bulk of them from the Far East, where gastric preparation for upper endoscopy is a routine procedure.