1. Carpenter assumed that increased fluid secretion began shortly after toxin administration but that net fluid production was not observed until the rate of secretion exceeded the rate of absorption. 2. It has also been shown that cholera toxin and heat stable enterotoxin of Escherichia coli can induce fluid secretion in the rat colon. 3. Both drugs significantly reduced fluid secretion or increased fluid absorption. 4. The effect was more pronounced the lower the rate of fluid absorption or the higher the rate of fluid secretion. 5. During the last decade evidence has been accumulating that fluid secretion in the small intestine is often evoked via stimulation of the enteric nervous system. 6. In eight animals lidocaine decreased fluid secretion or increased fluid absorption. 7. The quantitative effects of the drugs were related to the rate of fluid secretion or absorption. |