A new chemotherapeutic method for the treatment of tracheal and bronchial tree cancers, and of lung cancer with invasion to the bronchial tree has been developed. It is named Nebulization Chemotherapy or NC therapy. This method is based on vaporizing the anti-cancer drug (5-Fluorouracil, 5-FU) solution with a supersonic nebulizer, and inhaling the vaporized anticancer drug trans-orally through the bronchial tree. Patients were divided into two groups. The first group, where NC therapy was the main method of treatment used, included 6 patients. Of these, 4 (2CR and 2PR) showed a good anti-cancer response to the treatment. The other was a group receiving combination treatment with our CMAF protocol (cis-platinum, mitomycin C, adriamycin and 5-FU) and NC therapy. This group included 6 patients, 5 of whom (2CR, 2PR and 1MR) showed a remarkable anti-tumor response. Side-effects to the bronchial tree, pulmonary parenchyma or other systemic toxicity have not been noted so far after NC therapy. However, a few patients showed glottitis. Only trace amounts of circulating 5-FU were detected in serial serum samples.