horse chestnut. n. 1. Any of several trees of the genus Aesculus, especially the European species A. hippocastanum, having opposite, palmately compound leaves, erect clusters of white flowers tinged with red or yellow, and spiny or smooth capsules containing large shiny brown seeds.
Painful erections are very uncommon unless you have recently experienced penile trauma or irritation. Other causes of erectile pain would include: 1  Peyronie's disease. 2  Penile mass. 3  Priapism. 4  Phimosis. 5  Penile Injury.
Medical Factors Associated With Erectile Dysfunction. Medical conditions can cause ED in several different ways. Some of the most common medical causes of ED are diseases or injuries to the cardiovascular system. These can reduce blood flow to the penis. Nervous system problems can affect how signals travel to the blood vessels of the penis.