Abstract: OBJECTIVE: To investigate the potential chronic liver toxicity of oral administration of ethanol extract of Huangqin(Radix Scutellariae Baicalensis)(SBE) in Wistar rats.METHODS: SBE was administered to rats by gavage for 26 weeks, at doses of 300, 1250, or 2500 mg·kg-1·d-1 respectively. The rats were euthanized at the end of 13 and 26 weeks daily oral dosing and following 4 weeks of recovery time. The changes of hematology, urinary, blood biochemistry and histomorphology were examined at each time point and focus on liver function and histological changes.RESULTS: When SBE at a dose of up to 2500 mgkg-1 d-1 was fed to male and female rats for 2··6 weeks, the liver tissue showed some inflammatory change that predominated by leukocyte infiltrationbut returned to normal after withdrawal. In addition, high-dose SBE treatment of 26 weeks in rats,glucose, electrolyte and lipid levels also have some changes. In addition, there are no other functional or organic lesions related to SBE treatment.CONCLUSIONS: Long-term and high-dose SBE may cause liver damage, however, the structural damage of the liver can be restored after the ethanol extract stopping. SBE will be well-tolerated for long-term use as a drug or health food, but in order to ensure drug safety, liver function, and serum glucose, electrolyte and lipid levels should be monitored when using SBE long term.

Key words: Scutellaria baicalensis, Toxicity tests, chronic, Liver, Administration,oral