Birds' nest have been used for a long time in traditional Chinese medicine. It is classified as a cold food or ying according to the Chinese food concept. Birds' nest has been recommended for use in the curing or strengthening of the body in diseases related to weak blood or body overheat, cold, influenza, cough, asthma, and other bronchio ailments. Consumption of birds' nest is also recommended to complement other treatments to combat degenerative diseases such as cancer and also for convalescence or to recover health after illness or surgery.
It is also claimed that consuming birds' nests regularly can give a person exuberant physical and mental strength as well as to restore the fine and fair complexion of one's youthfulness. It is also mentioned that an expectant mother consuming birds' nests would have a baby with fine and smooth complexion. Chinese concept of food and medicine is a conspicuous part of the Chinese culture and birds' nest is one of the food items highly valued and often prescribed for use in the treatment of various body ailments.
The above is an extract taken from: http://birdnestman.tripod.com/