Gastrointestinal cancer is one of the health problems which is frequently found in many people in the world until now. Studies in gastrointestinal cancer showed early detection can reduce morbidity and improve the survival of patients. The precancerous lesions of the gastrointestinal tract are highly potential turn into cancer. Precancerous lesions can be defined as a change or non-cancerous lesions that can become cancerous over time. Precancerous lesions can be found on the entire upper and lower gastrointestinal tract. Precancerous lesions of the upper digestive tract that can be found are Barrett's esophagus, chronic gastritis with or without Helicobacter pylori infection, atrophic gastritis, intestinal metaplasia of the gastric mucosa, epithelial dysplasia, and adenoma polyp. While precancerous lesions in the lower gastrointestinal tract are adenoma, inflammatory bowel disease, chronic infection and hereditary non-polyposis colon lesions. Precancerous lesions of the stomach in the form of chronic atrophic gastritis, intestinal metaplasia and dysplasia can be treated with anti-inflammatory and anti-free radical drugs such as rebamipide and superoxide dysmutase. Precancerous lesions in the colon in the form of chronic enterocolitis, dysplasia can be treated with anti-oxidants, anti-inflammatory and anti-free radical such as anti-oxidants, rebamipide, superoxide dismutase, anti-inflammatory drugs.