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.
For your reference, the major physical causes of erectile dysfunction are: * Diabetes. * Heart disease. * High blood pressure (hypertension) * High cholesterol and poor blood circulation due to blocked arteries. * Surgery to the prostate, lower bowel or lower spine. * Liver and kidney disease.