Faecal tryptic activity in humans: influence of antibiotics on microbial intestinal degradation

Soluble faecal tryptic activity (FTA) was determined in healthy adults using a spectrophotometric method. Mean FTA was 100 mg/kg faeces (range 0-980), inter-individual variations were more pronounced than the intra-individual ones. Ten different antimicrobial drugs given orally for six days caused alterations in some individual FTA levels. Keywords: Tryptic activity; germfree life; intestinal flora; antibiotics.