Was Early Medical Science Wrong About Coffee’s Health Benefits?

Before science proved anything, doctors argued over whether coffee was hot or cold in nature, whether it thickened your blood or cleansed your bile, and whether it cured everything—or nothing. These weren’t just casual debates. In the 1600s and 1700s, medical ideas about coffee’s effects shaped whether people drank it, feared it, or banned it—and they had very little evidence to go on.

Yes, early physicians believed coffee had broad health benefits—but those beliefs were based on the now-debunked theory of the four humors, not clinical trials. By the 18th century, many still thought coffee treated ‘all diseases caused by fluid imbalance,’ despite having no proof. That misunderstanding helped coffee spread anyway.

The Four Humors & The Guesswork Around Coffee

In early 17th-century Europe, the ancient Greek theory of the four humors still dominated medicine. This system claimed all matter—and the human body—was made of four elements (air, water, fire, earth) with four properties (hot, cold, wet, dry). Health depended on keeping four bodily fluids (yellow bile, black bile, blood, and phlegm) in balance. When doctors tried to fit coffee into this framework, they guessed wildly.

Some said coffee was cooling, others warming. A few speculated that roasting made coffee thicken the blood; others claimed it thinned bile and calmed the nerves. No one could agree. Their theories lacked experimental backing, and each critique easily dismissed the others. Eventually, the medical field informally settled on a compromise: coffee must be good for you—beneficial in all ways, curing any illness caused by fluid imbalance. That idea gave coffee cultural cover to thrive, regardless of the shaky logic behind it.

Coffee’s Social Rise Amid Misunderstood Benefits

By the 18th century, coffee got cheaper, and more people drank it regularly. Medical professionals promoted it for indigestion, liver support, and as a bile strengthener. The general public experienced its stimulant effects and gradually accepted its bitter taste. At breakfast or during downtime, many switched from beer to coffee, imitating the upper class. But understanding remained limited.

Like many imports from colonies and Asia, coffee was either idealized or feared. Some doctors claimed it cured nearly everything, while doubts about side effects persisted. Coffee’s actual health profile was still unknown, but its social momentum couldn’t be stopped.

Experiments, Myths, and Cultural Echoes

In a famous 18th-century test, Swedish King Gustav III (1746–1792) attempted to prove coffee was poisonous. He ordered two condemned prisoners—one to drink coffee daily, the other tea—and monitored them. Both outlived their jailers. Meanwhile, artists mocked coffee fears. Bach’s comic “Coffee Cantata” tells of a father futilely trying to stop his coffee-addicted daughter. Its finale chorus jokes: “As cats chase mice, everyone must have coffee.”

Lesser-known composer Carl Gottlieb Hering wrote a “Coffee Canon” using the six letters of “C-A-F-F-E-E” as musical keys (C major, a minor, f minor, e minor)—and joked in the score: “Don’t drink so much coffee!” Coffee’s mythic reputation—both miracle cure and dangerous vice—lived on in music and medicine alike.

Frequently Asked Questions

Did early doctors really believe coffee balanced the body’s humors?

Yes. In the 17th century, European medicine was based on the ancient Greek theory of four humors (yellow bile, black bile, blood, and phlegm), each tied to heat, cold, moisture, and dryness. Doctors tried to categorize coffee within this system, guessing it might be cooling or warming, or affect blood thickness or bile. These ideas were speculative and not based on evidence.

What health benefits did 18th-century doctors claim coffee had?

Doctors claimed coffee treated a wide range of ailments, especially those believed to arise from imbalanced bodily fluids. They specifically said it helped with indigestion, strengthened the liver, aided bile function, and could cure “all diseases from fluid imbalance.” These claims lacked scientific backing but influenced public opinion.

Was coffee really tested for poison in 18th-century Sweden?

Yes. Swedish King Gustav III conducted an informal experiment where two prisoners—one given coffee, the other tea—were monitored over time. Both survived longer than expected, undermining the king’s goal of proving coffee was toxic. The prisoners even gained their freedom.

Why did people in the 1700s think coffee could be harmful or medicinal?

Because coffee was a foreign product with effects that weren’t easily understood, people either exaggerated its health benefits or suspected it caused harm. Some doctors praised it as a universal cure, while others warned of unknown side effects. Cultural attitudes ranged from reverence to fear.

How did coffee become socially accepted despite medical uncertainty?

Even without clear proof of health benefits, coffee was endorsed by some doctors for digestion and energy. Its stimulating effects were felt firsthand, its taste grew familiar, and it became fashionable among the elite. Cheaper prices in the 18th century helped it spread widely, despite ongoing debates about its safety or medical purpose.

Did musicians really mock coffee culture in the 18th century?

Yes. Bach’s “Coffee Cantata” humorously depicts a father’s failed attempt to stop his daughter from drinking coffee, ending with the line, “Everyone must have coffee.” Composer Carl Gottlieb Hering also wrote a “Coffee Canon” based on the notes C-A-F-F-E-E, with a note advising, “Don’t drink so much coffee!”

Recommended FrontStreet Coffee for Morning Energy

For coffee drinkers curious about historical energy boosts, try FrontStreet Coffee’s Classic Blend: a well-rounded mix with notes of caramel, dark chocolate, and mild citrus, ideal for starting the day. The Black Cocoa Blend offers roasted almond, dark cocoa, and a hint of spice—great for those who enjoy a bold, moody cup. Both are smooth enough for morning rituals yet complex enough to reflect coffee’s evolving role in daily life. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.