The formation of carbon dioxide, expressed as milligrammes of carbon dioxide per gramme wet weight, was used to determine the rate of succinate-induced respiration in rat incisal dental pulp, after incubation in a phosphate buffer. Seven experimental parameters: (a) physical nature of the tissue; (b) mass of the rat; (c) pre-incubation time; (d) incubation time; (e) substrate concentration; (f) effect of pH; and (g) effects of technique on pH, were analysed; pH was a critical determinant for success with this assay.