This is when a man cannot get, or keep, an erection that allows him to take part in sexual intercourse or other types of sexual activity.
Most men experience it at some time in their life, and the causes can be physical or psychological.
Physical causes include heart disease, diabetes and raised blood pressure. Alcohol, smoking and illegal drugs, as well as some prescription medicines, can also cause erectile problems.
Worries about work, money, your relationship, family and not getting an erection can all be factors.