High-dose probiotics do not prevent diarrhea in older hospitalized patients, according to a large study in the Lancet.

Nearly 3000 inpatients aged 65 and older who were on antibiotic therapy were randomized to 21 days of a placebo capsule or a capsule containing lactobacilli and bifidobacteria, taken once daily. After 8 weeks, the incidence of antibiotic-associated diarrhea or Clostridium difficile diarrhea did not differ significantly between the groups.

The authors conclude: “Our findings do not provide statistical evidence to support recommendations for the routine use of microbial preparations for the prevention” of diarrhea.

Source: Lancet