Starvation overnight and starvation for 48 h reduced the weight and the protein content of mucosal scrapings, but only minimally reduced the DNA content of the mucosal scrapings. The activity of sucrase and maltase was reduced by both periods of starvation. The activity of lactase and of acid and alkaline phosphatase, however, was less subject to starvation. There were striking differences in the response to starvation between the proximal, mid and distal third of the small intestine. The importance of the proper reference system was discussed.