What were the beliefs about causes of illness during the renaissance?

During the Renaissance, beliefs about the causes of illness were a blend of traditional and emerging ideas. Many still subscribed to the ancient humoral theory, which posited that an imbalance of the body's four humors (blood, phlegm, black bile, and yellow bile) caused disease. However, there was a growing interest in observation and anatomy, leading to a more scientific understanding of the body. This period also saw the beginnings of a shift towards recognizing environmental factors and contagion as potential causes of illness.