Abstract: [Abstract] Objective To investigate the Meeh constant(k) which could be used in the Meeh Formula to estimate the body surface area(BSA) of the C57BL/6 mouse when making its thermal injury model. Methods 24 normal C57BL/6 mice of 6-12 weeks age were randomly collected and intook normal diet until the experiment day. On the 3rd day before the experiment day, each mouse was weighted in every 4 hours. The next day, the 24 mice were randomly divided into 3 groups which congtained 4 male and 4 female mice. On the experiment day, the 1st group was anaesthetized, weighed and skinned at 8AM, while the 2nd group at 4PM and the 3rd one at 12PM. The BSA and k value of each mouse was recorded. Results The average weight of the 24 C57BL/6 mice reach its botton at 4PM and its top at 12PM. The calculated k value was 9.617±0.104 at 8AM, 9.802±0.110 at 4PM, and 9.570±0.244 at 12PM. There was statistical difference not only between the k value at 8AM and 4PM, but also between 4PM and 12PM. The k value which was often quoted as 9.1, 9.5, 10 or 11.4 when the literature dealing with the Meeh Formula of mice was reviewed. There was statistical difference not only between the often-quoted k value and the calculated k value at 8AM, but also between the often-quoted k value and the calculated k value at 4PM. Conclusions In the procedure of making the thermal injury model of C57BL/6 mice， it was reliable to use 9.617 as the k value to estimate the BSA at 8AM, but use 9.802 at 4PM.

Key words: Mice, Inbred C57BL, burn, body surface area