Taking an extract from shiitake mushrooms (AHCC) during pregnancy and breastfeeding can help protect babies from the negative immune effects of antibiotics. Antibiotics given early in life damage the beneficial bacteria in the baby’s gut, leading to long-term immune problems. This study showed that shiitake extract helped restore healthy bacteria and reduced inflammation in mice exposed to antibiotics as infants, suggesting it could be used as a preventive measure for children who need antibiotics.