The determination of volatile fatty acids in the caecum of the conscious rabbit.

1. A method of obtaining dialysed samples from the caecum of the conscious rabbit is described. 2. Values for total volatile fatty acid content and for molar proportions of individual volatile fatty acids in dialysate samples were in good agreement with those obtained from caecal material. 3. The volatile fatty acid level in the caecum throughout the day was determined using two groups of animals, one group fed ad lib. and the other group on a restricted food intake. These results indicated a marked diurnal fluctuation in volatile fatty acid level in the caecum of rabbits fed once/d which was not evident in those fed ad lib.