Why did people stop using leeches?

People largely stopped using leeches due to advances in medical science and a better understanding of human physiology. The development of antibiotics, antiseptics, and more effective surgical techniques made leech therapy seem outdated and often harmful. Additionally, the effectiveness of leeches for certain conditions was found to be limited, leading to their decline in favor of more scientifically validated treatments. Despite this, leeches have seen a resurgence in some specific medical applications, such as in reconstructive surgery for promoting blood flow.