Probiotics may reduce the risk for the onset of colorectal cancer by modulating the activity of fecal bacterial enzymes that catalyze the liberation of procarcinogenic substances in the intestine. The aim of this study was to investigate the influence of probiotic Lactobacillus helveticus MTCC 5463 (5463) on fecal microbial-related functions in geriatric volunteers. The subjects were randomized into 2 groups, fed either fermented drink containing 5463 (test group) or without 5463 (placebo group). The volunteers consumed 200 mL of the product once a day for 4 weeks. Fecal samples were collected in sterile plastic containers at the beginning and end of the intervention period. β-glucuronidase was considered as the marker enzyme for anti-colonic carcinogenesis activity, and measured in terms of unit activity per mg of protein in fecal samples. Total fecal protein was determined by Folin-Lowry method with bovine serum albumin as a standard. The data were analyzed with Student's t-test, and the levels of significance were expressed as p values. The mean β-glucuronidase activity was reduced in test group from 1.40 to 0.73 (μg/min/mg of protein) while in case of placebo group, no effect on enzyme activity was observed. Enzyme β-glucuronidase activity in the feces of all subjects in the probiotic group, were highly significant (P < 0.001), whereas the placebo group showed nonsignificant differences (P = 0.40). We were able to demonstrate consistent reduction in the fecal β-glucuronidase activity in the probiotic group. Results suggested that the metabolic activity of the fecal flora was altered by 5463 therapy, which further decreased procarcinogenic enzyme levels in the large intestine. Probiotic MTCC 5463 interaction with the geriatric host microbiome, affects β-glucuronidase activity, which can be exploited as an alternate therapy against colonic carcinogenesis.