Astrology was considered a legitimate science in medieval England and was frequently used by physicians to diagnose and treat illness. People believed that the positions of celestial bodies—especially the stars, sun, and planets—directly influenced human health. Physicians often consulted zodiac charts to determine when it was safe or dangerous to perform medical procedures, such as bloodletting or surgery. Each part of the body was believed to be governed by a different sign of the zodiac, and performing procedures when that sign was ascendant was thought to risk harm or death. For example, if Aries, associated with the head, was dominant, physicians would avoid operating on that region. Additionally, planetary alignments were used to explain sudden outbreaks of disease. A notable example occurred in 1345, when a rare conjunction of Saturn, Jupiter, and Mars was blamed for the arrival of the Black Death. This belief system gave people a sense of predictability and control over disease, even if it was inaccurate.

Dissection of human bodies was rare in medieval England primarily due to religious prohibitions and cultural beliefs. The Church taught that the body was sacred and should remain intact after death in preparation for resurrection. As a result, dissections were often viewed as disrespectful and sinful. When they did occur, they were usually on executed criminals and only under specific, tightly controlled conditions. This reluctance to study the human body directly meant that anatomical knowledge was extremely limited, and physicians relied heavily on the writings of ancient authorities like Galen, who had based much of his work on animal dissections. Since Galen’s work contained numerous inaccuracies, such as the belief that blood was produced in the liver and consumed by the body, these errors were passed down for centuries. The lack of direct observation and experimentation significantly slowed progress in understanding disease and human biology, reinforcing outdated explanations like the Four Humors and divine punishment.

Social class played a significant role in shaping how individuals understood the causes of disease in medieval England. Wealthier and educated people, including nobles, scholars, and physicians, had access to Latin texts and formal education. Their understanding of disease was influenced by classical authors like Hippocrates and Galen, and they often believed in the Theory of the Four Humors, astrology, and the miasma theory. These individuals could afford medical advice and treatments based on humoral theory. In contrast, peasants and the poor often relied on oral traditions, local folklore, and spiritual beliefs. They were more likely to believe that disease was caused by supernatural forces like evil spirits or the wrath of God, and they turned to charms, amulets, and local wise women for remedies. Without formal medical education, their understanding was shaped by experience and communal beliefs rather than rational or classical theories. This divide meant that interpretations of illness could vary dramatically between classes.

Classical Islamic scholars had a significant influence on the development of medical ideas in medieval England, particularly through the preservation and expansion of ancient Greek and Roman medical knowledge. During the Islamic Golden Age (8th–13th centuries), scholars like Avicenna (Ibn Sina) and Averroes (Ibn Rushd) translated and interpreted the works of Hippocrates and Galen into Arabic. They added their own observations and developed sophisticated medical texts such as Avicenna’s "Canon of Medicine," which became a foundational text in European medical education. These works were later translated into Latin and made their way into English universities and monastic libraries. Islamic scholars emphasized rational observation, diagnosis, and the use of herbal remedies, which complemented and extended Galenic theory. Their integration into the curriculum helped reinforce the Four Humors and broadened the understanding of disease causes, even though it remained within a largely pre-scientific framework. Thus, medieval English medicine was not isolated but part of a wider, interconnected intellectual tradition.

The absence of scientific tools and knowledge in medieval England severely restricted the development of accurate ideas about disease. Without technologies like microscopes, people could not observe bacteria, viruses, or the cellular structure of the human body. Consequently, diseases were interpreted through visible symptoms and existing beliefs rather than empirical evidence. There was no understanding of germs or infection; instead, people explained disease through divine punishment, supernatural forces, or imbalances of the Four Humors. The lack of standardized experimentation and controlled observation meant that theories could not be reliably tested or disproven. Moreover, medical training was based on ancient texts rather than new discoveries, and dissection was discouraged, limiting anatomical knowledge. This environment made it difficult for new ideas to emerge or for flawed theories to be challenged. As a result, even rational approaches like the miasma theory and humoral theory remained dominant for centuries, until advances in scientific thinking during the Renaissance began to change the medical landscape.