10785 Background: Sentinel lymph node biopsy (SLNB) is a very important method in detecting lymph nodes metastasis. There are several methods developed to detect sentinel lymph node. In this study, we will research on sentinel lymph node biopsy (SLNB) by using Chinese ink and study on its feasibility, clinical value and suitable concentration. Methods: Forty-two female rabbits were randomly divided into seven groups with 12 sides of mammaries (6 animals) in each group.The second mammary and the armpit of the same side were anatomized and injected 0.1 ml different dyes (1% isosulfan blue, 0.1%, 1%, 10%, 20%, 50%, 100% sterilized Chinese ink) at the base of the second mammary. We observed the dying time of the sentinel and the second lymph nodes and the fading time of the dying nodes. The pathological and histological examination of the sentinel lymph nodes were conducted in 5 minutes,1 hour and 2 weeks after the nodes were dyed by ink, respectively. The rabbits’ hearts, lungs, livers and kidneys were detected pathologic changes. Results: There was no obvious difference among different concentration ink on the dyeing time of the sentinel and second lymph nodes (P > 0.05),but distinctively different from 1% isosulfan blue (P < 0.05). There was no obvious difference between groups on the number of the dyed nodes (P > 0.05). But the nodes dyed by 0.1% ink were dyed too lightly to be found. The average fading time of the nodes dyed by 1% isosulfan bluewas 33.9 minutes, and the nodes dyed by ink were still dyed deeply 2 weeks after the experiment. The pathologic examination showed that the carbon aggregated in the lymph nodes sinus 5 minutes after the nodes were dyed, but was phagocytosed by Macrophage (MΦ) 1 hour after dyed. The groups (0.1%, 1%, 10% ink) showed good histology image, however, groups (20%, 50%, 100% ink) showed too much carbon aggregation to disturb the observation. There were no difference in blood routine and pathologic change between these two groups. Conclusions: Chinese ink of concentration 1% to 10% is a useful dye of SLNB according chromaticity, histological observation and security. This dye had latency clinical value and was a new type of the dye for SLNB. No significant financial relationships to disclose.