Honey should not be consumed by infants under 1 year of age because the botulism spores contained in honey can cause botulism in infants, putting their lives at risk.
"While there are multiple possible sources of infection for infant botulism, some cases have been associated with honey contaminated with spores. Therefore, parents and caregivers should be warned not to feed honey to infants until they are 1 year old." -- World Health Organization 2013.8
Clinical signs in infants include constipation, loss of appetite, weakness, altered crying, lethargy, droopy eyelids, and significant loss of head control. However, breastfeeding mothers can safely consume honey because botulism is not transmitted through breast milk.