According to the medieval science of medicine those suffering from the sickness of love i.e. the erotic melancholy will first fall into insomnia. This insomnia will waste the body by evaporating the vital bodily fluids from it and thereby breaking the balance between the four basic fluids in the body. The increasing dryness and the heating of the fluids will prevent the normal functioning of the four bodily fluids and the liver. As a result the person in love will become anorectic. His body will become all the more thinner and drier and his eyes will appear empty, hollow and tearless. In addition the people in love are pale and they sigh, their pulse will slow down in the moments of depression and rise when remembering the moments of joy.
A light diet, sleep, successive baths to nourish and moisten the body, letting out blood and intercourse (usually with someone other than the object of love) were recommended as cures for erotic melancholy. The more "psychological" cures included listening to music, discussing other subjects and travelling.
If these methods also failed to bring results i.e. to return the balance between the bodily fluids and the necessary moist, the continued overheating and overdrying started to produce melancholy fluids (melancholia adusta) in the body. As a result the body dried up completely and the skin turned dark. In a really serious case the result was insanity or death.
The last possible cure was usually considered to be the joining of the object of attraction to his admirer.
Taken from: http://www.tkukoulu.fi/WindMills/en-lemmensairaus.html