RESULTS	During the 7 days period , the rate of AAD was 7.8 % ( 13/193 ) in treatment group and 16.8 % ( 30/179 ) in control group , there was significant difference ; compared with the control group , the treatment with Clostridium butyricum and Bifidobacterium combined Powder can lead to 53.6 % reduction in AAD risk ( RR = 0.419 , 95 % CI 0.217 - 0.808 ; P = 0.008 ) .\