Benadryl is generally not safe to give to babies or infants under 2 years old at home. Sometimes, people can safely give infants aged 2 to 5 small doses of Benadryl, but only when a doctor advises them to do so. Specific child-friendly Benadryl is available for children aged 6 and above.

Therefore, Benadryl is not safe for infants as a general rule. This is because the active ingredient diphenhydramine is an antihistamine, which can be dangerous to children younger than two. Because Benadryl is an antihistamine, it can cause serious or even fatal side effects in infants.