In siddha called Moolam. Hemorrhoids also known as piles,piles are swollen veins in the lowest part of your rectum and anus. Sometimes the walls of these blood vessels stretch so thin that the veins bulge and get irritated

Piles - Hemorrhoid

When you  are constipated, you are more likely to push hard to try to go. That can make the veins around your rectum and anus swell. These swollen veins are called hemorrhoids, or piles. They are like varicose veins around your anus.