Can some probiotics have an antibiotic effect?

The Claim: Some probiotics, healthy bacteria commonly known for improving digestion and boosting the immune system, also can kill pathogens, such as those that cause food poisoning and others that cause illnesses such as strep throat.

The Verdict: A probiotic lozenge can reduce incidence of strep throat, according to published research by Italian scientists. A Harvard University scientist found another strain, which is added to some smoothies and raw juices, can kill a wide variety of harmful bacteria in lab tests. The use of probiotics to kill pathogens is a promising area but most of the work is still preliminary, scientists say.

The ability of some bacteria to kill other bacteria isn’t new—foods such as yogurt, sauerkraut and pickled cucumbers are preserved thanks to a type of bacteria that produces lactic acid, which is lethal to harmful bacteria, says Maria L. Marco, associate professor in the Department of Food Science & Technology at the University of California, Davis.