['Prophylactic probiotics to reduce necrotising enterocolitis (NEC) are mostly given for at least 28 days or until discharge. We describe the effects of a shorter duration dosing strategy.', 'Retrospective cohort study of neonates (birthweight 400-1500 g) in three neonatal intensive care units in Switzerland and Germany that embarked on probiotic prophylaxis given for 10 or 14 days, employing a fixed combination (Lactobacillus acidophilus plus Bifidobacterium infantis, each 10(9) CFU/day) licensed as a drug in Switzerland. Probiotics were initiated upon discontinuation of antibiotics, or on day 1-3 in infants without antibiotics. Repeat probiotic courses were given whenever antibiotics had been instituted and were discontinued.', 'Birthweight and gestational age were similar in the two 24-month pre- and postimplementation cohorts. NEC rates fell from 33 of 633 (5.2%) to 8 of 591 infants alive at three days (1.4%; risk ratio (RR) 0.26, 95% confidence interval (CI) 0.12-0.55). The drop in NEC was significant both for infants of 400-999 g (6.4% to 2.5%) and 1000-1500 g birthweight (4.4% to 0.6%). Mortality was 5.1% (32/633) without, as opposed to 3.5% (21/591) with probiotics, respectively (RR 0.69, 95% CI 0.41-1.19).'] Do short courses of dual-strain probiotics appear to be effective in reducing necrotising enterocolitis?