Honeymoon rhinitis (or honeymoon nose) is a condition in which the sufferer experiences nasal congestion during sexual intercourse or arousal.^[1]

The condition appears to be genetically determined and caused by the presence in the nose of erectile tissue which may become engorged during sexual arousal, as a side effect of the signals from the autonomic nervous system that trigger changes in the genitals of both men and women.

A related condition called sexually induced sneezing also exists, where people sneeze, sometimes uncontrollably, when engaging in or even thinking about sexual activity.^[2]

A phenomenon presumably related to honeymoon rhinitis is the frequent side effect of nasal congestion during the use of sildenafil or related phosphodiesterase type 5 antagonists.^[3]