MA-3 is an unique liquid formula for tube feeding which contains casein and starch hydrolysates and aseptically packaged for an individual patient. Remarkable progresses in MA-3, as compared with the conventional powdered formula, have been made to accomplish its negligible bacterial contamination, limited fluctuation in the composition and feasibility in feeding practice. Authors previously reported the tube feeding of MA-3 to the subjects who received surgery of esophageal carcinoma. In the present article, the results of clinical studies are described on tube feeding of MA-3 by means of jejunal fistula to those 2 patients for 1, 296 and 190 days, who have undergone the surgical excision against non-neoplastic and neoplastic lesions respectively at the digestive tract. 1. Diarrhea was by no means observed in both subjects who fed MA-3. This seemed to be due to dietary significance of MA-3 and favorable adjustment of the feeding rate. 2. The energies which effected to keep the constant body weight of 51 and 46kg in the former and the latter subjects were 27.5 and 43.8kcal/kg of body weight respectively. 3. Nutritional value of MA-3 was determined in terms of the protein level in blood serum. Blood analysis against the former subject at the moment of remission revealed the total protein concentration of 6.2 to 6.5g/dl in blood serum and 12.0 to 12.5g/dl in hemoglobin value. The protein uptake and kcal/N value were 0.67g/kg and 262kcal/kg respectively. Nitrogen balance was noted to be +1.35 while the result of occult blood test, an index for homorrhage in digestive tract, was evidently positive. In the latter subject who manifested hepatic dysfunction, protein uptake and kcal/N value were 0.78g/kg and 272kcal/kg respectively. GOT and GPT values remained constant throughout the period of the present study.