OBJECTIVE: To compare the distribution of levofloxacin in lung of mice after intragastric and intravenous administration of Tanreqing injection combined with levofloxacin. METHODS: 144 mice were randomly divided into experimental group and control group, with 72 mice in each group. Both groups were given Tanreqing injection (0.8 ml/kg). 1 h later, control group was given Levofloxacin injection (80 mg/kg) intravenously, and experimental group Levofloxacin tablet solution (80 mg/kg) intragastrically; every 8 mice were sacrificed for lung tissue collection at the time points of 0.05, 0.083, 0.17, 0.5, 1.0, 2.0, 4.0, 8.0, 12.0 h and 0.083, 0.17, 0.33, 0.5, 1.0, 2.0, 4.0, 8.0, 12.0 h, respectively. Using ciprofloxacin as internal standard, the content of levofloxacin in lung tissue was determined by HPLC, and pharmacokinetic parameters were calculated by 3p97 program. RESULTS: The concentration-time curves of levofloxacin in lung tissue were in line with two-compartment model in 2 groups. The main pharmacokinetics of experimental group and control group were as follows as t1/2β of (4.17±0.84) h and (4.10±0.55) h; CL of (0.66±0.049) L/h and (0.71±0.21) L/h; AUC0-t of (109.48±12.34) mg·h/kg and (113.04±29.43) mg·h/kg; cmax of (38.76±1.62) mg/kg and (42.28±2.03) mg/kg, respectively. There was no statistical significance (P>0.05). Absolute bioavailability of levofloxacin was(96.85±17.39)% in experimental group with intragastric administration. CONCLUSIONS: After intravenous injection of Tanreqing injection, the distribution of levofloxacin in lung tissue of mice are similiar between intragastric administration and intragastric administration.