This paper describes a study on tests for bacterial endotoxin of compound amino acid injection (18AA), compound amino acid injection ( 1 5AA) ,six amino acids injection and ciprofloxacin lactate injection. Interference test and confirmatory test revealed an interference existed in tests for bacterial endotoxin of four fluid infusions. When diluting to 4 times to make = 0. 125EU/ml of TAL reagent,the interference can be avoided. Test for bacterial endotoxin may take the place of test for pyro-gens in above four articles.