Phlegmatic is one of the four aspects that make up the humorism system of medicine. Also known as the humoral theory, this was a medicinal theory that Ancient Greeks and Romans used to explain many of the conditions that could affect the body. Though the concept originated in Greece, the four humors inspired medicinal and psychological systems throughout the world.

The Four Humors

The most popular theory of humorism holds that there are four humors and temperaments: phlegmatic, sanguine, melancholic, and choleric. These humors have associations with a physical liquid, as well as the four elements, nature, seasons, personalities, and a range of health conditions. According to humorism, a person’s four humors had to remain in balance to achieve perfect health.

four humors concept with eggs


Phlegmatic Medicinal Beliefs

Humoral theory suggested that an excess of one of the four humors, phlegm, was responsible for forgetfulness, white hair, and withdrawn behavior. Most people believed that the brain and lungs created phlegm due to exposure to hot air or moist foods. They also suggested that phlegm could cause tumor development, chlorosis, and rheumatism.

older woman holding out her sore hand


Humor Production

Ancient physicians believed that the four humors were products of hepatic digestion. In this theory, the body transforms food into chylous, which then becomes chymous, which consists of the four humors. The chymous and humors circulate through the body. Anything that interfered with this process could cause a variety of issues. For example, humorism suggests that hot winds could trigger digestive issues by making excess phlegm flow from the head.

woman sitting on bed with stomach pain


Phlegm in Islamic Medicine

Greek humorism had a major impact on Islamic medicine and led to the development of a system that some cultures continue to practice. This system has closer ties to the elements, as well as explaining more specific health conditions. A phlegmatic person has associations with moisture. This causes fatigue, digestive issues, sleepiness, diarrhea, rough skin, swollen eyelids, and habit formation.

woman at office yawning at her desk


Phlegmatic People in Western Medicine

Humorism continued to dominate the view of the human body for European physicians until well into the 1500s, though they may have persisted much longer in some areas. As an example, practices such as bleeding an ill person or applying hot cups have links to humorism. For phlegmatic individuals, Western doctors believed that the lungs produced phlegm due to excess moisture or cold. Signs of a phlegmatic person included excess fat and sluggish behavior.

business woman falling asleep at her desk on laptop


Phlegmatic Humor in the Modern World

Despite sharing a name, the phlegm of humorism has nothing to do with the modern definition of the word. Experts and most people view humorism as a pseudoscience. However, the humorist concept of a person’s environment affecting their temperament has appealed to many individuals. This has led to some psychologists adopting humorism temperaments into their work.

male patient speaking with psychologist


The Shift into the Four Temperaments

Originally, the four humors referred exclusively to bodily fluids. Galen, a philosopher and physician, believed that each humor corresponded to certain behaviors. This quickly led to the recognition of personality and temperament resulting from humoral imbalance. Some of the oldest humoral systems state that phlegmatic people are low-spirited, frequently fatigued, and act shy or reserved. Galen thought that a phlegmatic person was dependable, kind, and affectionate.

smiling woman and little girl in kitchen, hugging


Phlegmatic Temperament Across Systems

Over the years, many different psychologists and philosophers have adapted the four temperaments into new systems. Some examples of a phlegmatic temperament in these systems include:

  • Adler: Getting type, lacks energy, indifferent to life, slow and sluggish, receives rather than gives

  • Riemann: Schizoid, anxious and aggressive, few to no emotional bonds

person taking a multiple choice test


Phlegmatic Behavioral Signs

With a few exceptions, each system recognizes phlegmatic individuals as relaxed, peaceful, easy-going, and quiet. While they tend to hide their emotions, they are sympathetic and care about others. Most people would identify a phlegmatic personality as an introverted one. Some systems link phlegmatic people to anxiety disorders and similar issues.

personality profile assessment test on clipboard


Phlegmatic Temperament in the Modern World

While few modern institutions actively use the phrase “phlegmatic,” the concept of phlegmatic temperament is still popular and some are traceable back to the original temperament theory. Two examples of this are the Myers-Briggs Type Indicator (MBTI) and the Keirsey Temperament Sorter. These systems break the original four temperaments into two roles, each with two types, for a total of 16 personality types. Phlegmatic individuals fall under the MBTI sensing-judging (SJ) types and the Keirsey Guardian type.

list of myers-briggs personality types


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