The efficacy of Broncho-Vaxom/Imocur (OM-85 BV), an orally administered lyophilized bacterial extract, for recurrent respiratory and ear, nose and throat (ENT) infections was evaluated in 116 children aged 6 months to 19 years by comparing its activity in 61 children with that of a placebo in 55 children. The study was randomized, double-blind, and comprised a 90-day treatment period followed by a 90-day follow-up period without test drugs. Over the 180 days, 39.5% of patients taking OM-85 BV remained free from infection compared with 16.5% on placebo (p less than 0.01). 44% on OM-85 BV did not need antibiotics compared with 23.5% on placebo (p less than 0.05). These differences were even greater in the subgroup of children aged 6 years and less (34 vs. 3.5% for the absence of infections, p less than 0.01 and 37 vs. 10% for the need of antibiotics, p less than 0.05). Tolerance to OM-85 BV was excellent, and laboratory investigations showed no abnormalities attributable to this product. This work confirms that the immunomodulator OM-85 BV is an effective immunotherapy for recurrent respiratory and ENT infections in children.