Six patients unfit for surgery with colonic sessile villous adenomas were treated by Nd:YAG laser. There were 3 women and 3 men, 68 to 86 years old (mean ± SD 78 ± 8 years). The tumors varied in size from 3 to 6 em. Three villous adenomas were located in the sigmoid, two in the transverse colon, and one in the right colon. Histologic examination revealed areas of moderate dysplasia in all cases. Patients were treated twice a week until the physician had created the maximal endoscopic effect. An average number of five sessions (range, five to eight) were necessary before the entire lesion was removed. Then the border of the base of the lesion was marked circumferentially at endoscopy with 4 ml of a charcoal suspension in four separate injections of 1 ml each. The suspension of charcoal was a 5% weight/volume aqueous suspension of micronized particles, 2 to 5 JLm in diameter. The carbonaceous raw material was peat and obtained from Norit (Prolabo, Paris, France); the charcoal was weakly activated, i.e., the surface area as determined by BET (Brunauer, Emmet, Tayler)5 adsorption was 600 m/g. The suspension was sterilized at 120°C for 20 min. The sterility was tested as described in the European Pharmacopeia,s and the concentration of bacterial endotoxin was determined using limulus amebocyte lysate.? The preparation was found to be sterile and pyrogen free. This preparation is not currently commercially available. The charcoal suspension was shaken well, drawn into a 5-ml syringe, and injected via a sclerotherapy media (ABS TW4-6D, SaintDie Cedex, France) through the biopsy channel ofthe colonoscope. After documented endoscopic and histologic ablation of the villous adenoma, endoscopy with multiple biopsies