High intake of Benadryl can lead to serious heart problems ... Benadryl is generally safe, but taking more than the ...

The Food and Drug Administration (FDA) has not approved Benadryl, which contains the active ingredient diphenhydramine, to treat anxiety. The medication is also not intended for long-term use.

Related: Benadryl for Dogs: Side Effects of Long-Term Use At normal doses, Benadryl is quite safe, but a survey of over 600 dogs (1) found the following signs of overdose: Three of the dogs in ...