Do not give honey to a child under 1 year old

High value
Evidence A
Buys life
For: Child under 3, Pregnant or trying
Free
Takes minutes
No willpower

In plain words

Do not give honey to a child under 1 year old. This includes honey water, honey stirred into solid food, and pastries made with honey. Honey can carry bacteria that cause botulism. The gut flora of an adult can hold them down, but an infant's cannot. Home-made pickles and fermented foods follow the same reasoning.

Cost: Free.
What you get: The U.S. Centers for Disease Control and Prevention says "do not feed honey to children under 1 year old," because "honey can contain bacteria that cause botulism." The gut flora of adults can hold down these spores (the dormant form of the bacteria), but an infant's cannot.
Notes: What must not be given includes honey water, solid food mixed with honey, and pastries containing honey. By the same reasoning, don't give infants home-made pickles or fermented foods.
Evidence grade: A : Specific numbers from meta-analyses, large cohorts or randomized trials; for law and policy, the statute or official text.
Sources: US CDC. Preventing Botulism. https://www.cdc.gov/botulism/prevention/index.html

Mentioned in

Don't give a child under 2 combination cold medicines or cough medicines on your own for a cold

Translated from the Chinese original. Original book, section 20, tip 6. This section is about health and medicines. It is general information, not a substitute for a doctor’s diagnosis or prescription. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer