There is convincing evidence that breast-feeding is protective against gastro-enteritis and diarrhoea, but for other infections the situation is less clear cut. There is evidence that breast-fed infants are at increased risk of one infection (infant botulism). They are probably not significantly protected from upper respiratory tract infections (other than otitis media.), but they may be at a decreased risk of lower respiratory tract infections, particularly those associated with respiratory syncytial virus. There is strong evidence that Haemophilus influenzae B infection is more likely in the bottle-fed infant, and consistent evidence of protection of young children from chronic otitis media with prolonged breast-feeding.