he minimum inhibitory concentration(MIC) of 4 antibacterial agents on helicobacter pylori(HP) was tested by the agr double dilution methods. Minimum inhibitory concentration (MIC)

MIC50 and MIC90 were used to evaluate their antibacterial activity.The results showed that MIC

MIC50 and MIC90 were 5-100μg/ml

20μg/ml

and 50μg/ml for tripotassium dicitrate bi-smuthate(TDB) in 42 HP trains

0.004 - 0.125μg/ml

0.016μg/ml

and 0.063μg/ml

for ampicillin in 32 HPtrains

0.002 - 0.25μg/ml

0.031μg/ml

and 0.063μg/ml

for Cefazolin in 32 HP trains

and 0.5-16μg/ml

2μg/ml

and 16μg/ml for norfloxacin in 26 HP trains

respectively.The MIC of TDB were higher thanthose of other three drugs. This experiment indicats that some antibacterial agents can inhibite HPeffectively

but the partial resistant HP trains to drugs may exist.