From Ancient Springs to Modern Medicine

The healing power of carbon dioxide–rich waters is not a modern discovery. Its roots stretch deep into history, connecting today’s clinical CO₂ applications with ancient bathing traditions. Natural mineral springs are widely distributed throughout the world but are most numerous in areas where volcanic activity has occurred in recent geologic time [ref1].

The word spa may be derived from the Walloon word espa, meaning fountain—originally from the name of the Belgian town Spa, where a curative thermal spring was discovered in the 14th century. Alternatively, it may come from the Latin spagere (“to scatter, sprinkle, moisten”) or from the acronym sanitas per aquas (“health through water”) [ref2], [ref3].

Greek and Roman Beginnings

In ancient Greece, bathing was considered essential to a balanced life. Mineral springs—often naturally charged with dissolved CO₂—were used to refresh the body, soothe sore muscles, and restore vitality after exertion. Public baths served not just as places of cleansing but as social and educational centers, combining physical care with intellectual exchange. This era set the stage for centuries of CO₂-based bathing traditions, where the mineral sparkle of the water became a symbol of vitality and resilience.

The Romans adopted and expanded these traditions, constructing vast public bath complexes (thermae) supplied by mineral springs. These waters, often naturally carbonated, produced a gentle effervescence that stimulated the skin and circulation. Roman physicians prescribed bathing and drinking cures for digestive complaints, circulatory problems, wound healing, and general restoration of strength. Historical records show that mineral waters with “liveliness” or “sparkle” were especially prized, though their CO₂ content would not be scientifically understood until centuries later.

During the height of Roman bathing culture, Rome’s inhabitants used an estimated 1,400 liters of water per person per day—ten times modern consumption. Each day, 750 million liters flowed through 13 aqueducts, feeding 1,352 public fountains, 11 imperial thermae, and 926 public baths [ref4]. Roman legions built their own baths near mineral and thermal springs in newly conquered lands, a tradition still visible in the archaeological remains of spa towns across Europe.

Roman engineers elevated the use of mineral-rich, CO₂-containing spring waters into an art form, constructing elaborate thermae complexes that combined bathing, socializing, and convalescence. This tradition spread throughout the empire, leaving an enduring legacy still visible in European spa towns today. 

The benefits were so valued that entire spa towns and resort complexes developed around these springs, blending health, leisure, and social life. Roman thermae became hubs for physical restoration and community gathering. Some of the Roman bathhouses were spectacular achievements even by modern-day standards. Diocletian's bathhouse in Rome covered an area of over 13 hectares, about 32.5 acres —and could accommodate as many as 3,000 people [ref5].

Decline and Preservation

Thermae were social gathering places where friends met and talked, business meetings were held, and various entertainments were performed. Actors, jugglers, slaves, and beauticians scurried around, tending to the needs of their masters and clientele. Those who could afford slaves brought them to the baths so that the slaves could rub down, massage, and anoint their masters. Over time, the Roman baths became centers for various sexual practices. Deterioration of morals became manifest, the hygienic and medical indications for bathing disappeared, and baths as a haunt for pleasure ruled. The word "bagnio," meaning a brothel, actually derives from the Latin word for bath, "balneum".

There is a saying that Rome fell because too many people spent too much time in the public baths, which is probably not too far from the truth. The Roman Emperor Theodosius I, through the Edict of Thessalonica in 380 AD, made Nicene Christianity the state religion of the Roman Empire. With the fall of the Roman Empire in 476 and the rise of Christianity, the bathing culture fell into disrepute, and bathing was officially prohibited. Faith in a cure through worship and prayer was regarded as more important than a medicinal bath. Baths were redeveloped as churches, although some remained available for the aristocrats who were not affected by the church’s decrees.

Early Christians viewed the public bathhouses that the Romans had spawned all over Europe as immoral and unnecessary. Cleanliness was equated with the luxury, materialism, and excessive sensualism of Rome; this made dirt a badge of holiness, and not washing oneself a pious act of self-denial. Many abstained from bathing altogether, thus mortifying the flesh as a penance for sin, while others retreated to private baths.

Yet in regions under Moorish influence, communal bathing continued, keeping alive the knowledge of mineral water’s therapeutic power. The Moors, who were primarily Arab and Berber Muslims, significantly influenced Spanish culture and society during their nearly 800-year rule (from the 8th to the 15th century).

Renaissance Revival

The Renaissance brought renewed medical interest in mineral springs. Physicians began classifying waters by temperature, taste, and observed effects, marking the birth of balneology, the science dealing with the therapeutic effects of baths and bathing, as a formal discipline. CO₂-rich waters were prescribed for circulatory disorders, digestive complaints, and skin ailments. Treatments often combined bathing, drinking cures, mud applications, and lifestyle prescriptions—an approach strikingly similar to modern CO₂ spa programs. Such practices bridge the wisdom of the past with the precision of modern medicine, creating a continuum of care that spans millennia.

Across Cultures

In Japan, onsen culture has flourished for over a thousand years. Among the many spring types, carbonated springs (tansan-sen) have been especially valued for promoting blood flow, aiding wound recovery, and easing fatigue. Today, Japan boasts hundreds of natural CO₂ hot springs, such as Nagayu Onsen in Ōita Prefecture, where visitors can both bathe in and drink the mineral-rich water [ref6]. These traditions were not only about bathing, but also about connecting—to nature, to community, and to the body’s own ability to heal and recharge.

Early Chinese writings are full of respect for the rejuvenating power of natural springs. Wang Chia of the Chin Dynasty (200 BCE) wrote that “the bubbling fountain of Pon Lai gives a thousand lives to those who drink it.” Likewise, the springs of Mount Lao Shan had the reputation of being the elixir of life, drawing emperors of the Chin and Han dynasties on pilgrimage [ref4].

Timeless Benefits

For the Greeks, Romans, Japanese, Chinese, and many other ancient cultures, bathing in naturally carbonated waters was more than a leisure activity—it was a health intervention. These CO₂-rich springs were used to:

What the ancients experienced firsthand is now understood scientifically: CO₂ is the main active ingredient in many therapeutic hot springs, where it seeps naturally from underground sources. Immersion in these CO₂-rich waters improves circulation, supports relaxation, and promotes recovery—demonstrating that CO₂ therapy has been around for centuries, long before it was formally studied in laboratories and clinics.

The First Medical CO₂ Therapies

While CO₂’s healing presence in mineral baths was known for centuries, its direct medical application began to be documented in the 18th century. In 1794, Dr. John Ewart of the Bath City Infirmary in the United Kingdom developed a novel apparatus to deliver CO₂ gas directly to ulcerated breast cancers. Generated by combining limestone with sulfuric acid, the gas was contained in a bladder secured over the wound. The results were striking: patients reported immediate pain relief, reduced odor, and visible wound healing. In one case, the ulcer closed entirely; in another, severe pain vanished, and general health improved despite the disease’s severity.

Ewart noted that earlier attempts to treat cancers with CO₂ had failed because the gas dissipated too quickly. His innovation—keeping CO₂ in prolonged, direct contact with tissue—ensured continuous exposure, which he believed excluded atmospheric oxygen (a possible irritant) and allowed the wound to heal in a more favorable environment.

As Ewart himself observed: "One woman, who had an open ulcer on her breast for six years, measuring 13 x 10 x 6 centimeters, had less than a third after 28 days of applying the CO₂ gas. What strikes us, with the greatest astonishment, is the almost instantaneous relief of pain, which never failed to follow the application of the CO₂ gas" [ref7].

Dr. Ewart’s innovation exposed the ulcerated breast to continuous CO₂.

The Bath General Hospital

From Roman times until the late 19th century, lead poisoning was a common but poorly recognized problem. Many communities used lead pipes for carrying water, lead-glazed pottery for food and drink, cooking vessels lined with tin-lead mixtures, pewter plates and tankards, and lead-lined sinks and storage boxes. Lead was also found in cosmetics, food colorants, and even medicines, allowing significant exposure over a lifetime.

The Bath General Hospital, opened in 1741, aimed to demonstrate the value of Bath’s spa waters in treating a wide range of diseases. Hospital records show that one condition particularly responsive to treatment was the paralysis caused by chronic lead intoxication (colica pictonum). Between 1760 and 1879, the hospital admitted 3,377 such cases—representing 6.9% of all admissions. Of these patients, 45% were discharged as cured, and 93% showed significant improvement [ref8]. This stands as one of history’s clearest proofs that naturally carbonated waters could heal long before science explained how.

A direct comparison between Bath and Exeter hospitals highlights the difference. Between 1762 and 1767, Exeter admitted 285 patients with colica pictonum, curing or improving 73%. Bath treated 281 patients during the same period, curing or improving 93%—a figure that included around 80 patients referred from Exeter after unsuccessful treatment there [ref8].

The high success rates in Bath were likely due to several factors, with the high content of naturally dissolved CO₂ in Bath’s waters probably playing the leading role.

CO₂ in 19th and Early 20th Century Medicine

Medical interest in CO₂ expanded in the 1800s. Dr. Achilles Rose, in his work Carbon Dioxide in Medicine, published in 1905, detailed its uses for improving circulation, relieving muscle spasms, and aiding tissue recovery. CO₂ baths and local applications were prescribed for chronic wounds, gangrene, joint problems, circulatory disorders, and gynecological conditions like dysmenorrhea, providing relief from menstrual pain. European “dry gas” CO₂ chambers emerged in health spas, especially in Germany and the Czech Republic, treating heart and vascular conditions with controlled CO₂ exposure.

Physicians observed that CO₂ therapy often produced warmth, flushing of the skin, and a sense of relaxation—clear signs of vasodilation and parasympathetic activation. These effects mirrored what bathers had long experienced in natural carbonated springs.

Rose emphasized its importance: "Carbon dioxide acts as a stimulant to the skin and underlying tissues, improving circulation and promoting the resolution of chronic conditions." [ref9]

CO₂ baths at the Manhattan State Hospital in 1895.

From Spa Tradition to Clinical Practice

By the early 20th century, CO₂ therapy had a foothold in both spa medicine and hospital practice. In Europe and Japan, CO₂-rich baths remained part of state-supported rehabilitation programs. In clinical settings, transcutaneous CO₂ application, CO₂-enriched hydrotherapy, and inhalation methods were explored for wound care, circulatory health, and pain management.

Today, research continues to validate what both ancient cultures and early physicians discovered: CO₂, far from being a mere “waste gas,” is a potent therapeutic agent when applied with skill and precision.

Drinking Naturally Carbonated Waters

The benefits of CO₂ therapy are not limited to bathing or topical application—many springs around the world produce naturally carbonated waters that are safe, and even beneficial, to drink. Formed when groundwater meets CO₂ trapped in underground rock formations, these waters are naturally infused with dissolved carbon dioxide and often rich in minerals.

Some famous examples include Perrier Spring in Vergèze, France — renowned since Roman times and still bottled today, and Gerolsteiner in Germany — producing mineral-rich sparkling water since 1888 [ref10].

Historically, such waters were prescribed for digestive health, kidney function, and general vitality. Modern research supports these uses, noting that mineral carbonated water can aid hydration, support stomach function, and provide beneficial trace minerals—without the additives of artificially carbonated soft drinks.

CO₂ Spas in the Modern Era

While CO₂ therapy’s roots lie deep in ancient traditions, many spa towns around the world continue to offer it today—combining historical charm, mineral-rich waters, and advanced therapeutic programs. Here are a few examples.

Royat, France – Volcanic Waters and Belle Époque Elegance
Built on an ancient Roman spa site in France’s volcanic Massif Central, Royat has drawn visitors for over 2,000 years. The Roman thermal complex featured three large pools and four rooms heated by geothermal energy. Fragments of multicoloured marble, mosaics, and bronze bear witness to the site's once luxurious decor.

In modern times, the resort boomed with the arrival of Napoleon III and Empress Eugénie in 1862. Its five natural springs—rich in CO₂, iron, and lithium—are prescribed for cardiovascular health and other conditions. Treatments also include CO₂ injections under the skin, a method pioneered here in the 1930s [ref11]. Napoleon’s presence here cemented Royat's reputation as a destination where elegance met genuine medical benefit.

Mariánské Lázně, Czech Republic – The City of a Hundred Springs
Founded in 1197 by monks, this elegant resort is located at 600 meters at the foot of a protected landscape area. In the countryside around the town, some 100 springs rise from the ground, and within the town itself, there are 40 springs, many naturally carbonated. The CO₂-rich water is used for drinking cures, inhalations, and baths.

The town also offers unique CO₂ therapies such as dry gas baths and gas injections—aimed at improving circulation, reducing inflammation, and enhancing sexual ability. Prominent visitors include composers like Strauss, Beethoven, Wagner, and Chopin, as well as writers like Goethe, Nietzsche, Kafka, Twain, and Kipling, and even royalties like King Edward VII, Emperor Franz Josef, and Czar Nicholas II [ref12], [ref13].

The singing fountain at Mariánské Lázně plays musical compositions to honor the writers and composers who went there for inspiration.

Nagayu Onsen, Japan – The Nation’s Soda Springs Capital
Nagayu Onsen in Ōita Prefecture offers the highest natural CO₂ concentration in Japan. Bathers experience a fizzy sensation as bubbles cling to the skin, dilating capillaries and improving circulation. The water is believed to help with neuralgia, muscle pain, and fatigue, while drinking the spring water is said to benefit the heart, stomach, and intestines. The town’s baths, some designed by famous architects, showcase how Japan blends functional health treatments with cultural and aesthetic refinement [ref6].

CO₂ Therapy and Sexual Vitality in Transylvania
In the heart of Transylvania, in Covasna County’s cardiology hospital, patients “bathe” in naturally occurring CO₂ that seeps from deep volcanic fissures. The treatment takes place fully clothed in a quiet wooden amphitheatre. Participants stand in the dense gas—averaging 96% CO₂—which gently seeps through fabric and skin, triggering powerful vasodilation.

As the blood flows more freely to the pelvic zone, this warming, tingling sensation has earned the treatment its local nickname—the “natural viagra.” For healthy visitors, this surge of pelvic blood flow is seen as an aphrodisiac; for those with cardiovascular challenges, it offers a safe, non-invasive way to improve peripheral circulation and vitality.
The experience is carefully managed—CO₂ is heavier than air, so it pools near the ground without risk of suffocation if one keeps the head above the gas line. [ref3]

From Ancient Ritual to Modern Wellness

From Roman bathhouses to Japanese onsen, from 19th-century European spa palaces to today’s CO₂ wellness resorts, one truth has endured: carbon dioxide, far from being a waste product, is a vital part of human health. Across centuries and cultures, CO₂-rich waters have been sought out for their ability to restore vitality, ease pain, improve circulation, and rejuvenate skin quality.

Modern science has begun to explain what ancient people already sensed—CO₂ therapies, whether through bathing, drinking, or targeted medical application, help the body heal by opening blood vessels, supporting oxygen delivery, and calming the nervous system. The spa towns of today are not just guardians of a historic tradition; they are living laboratories where timeless natural remedies meet modern wellness practices.

In rediscovering and embracing CO₂ therapy, we are not simply reviving an old custom—we are reconnecting with a global heritage of healing that has proven its value for thousands of years — and continues to offer profound benefits for body and mind today Modern clinical studies confirm that CO₂ therapy improves circulation and skin conditions, supports oxygen delivery, and enhances tissue healing in cardiovascular and musculoskeletal conditions [ref14], [ref15], [ref16], [ref17], [ref18].

References

1. Thermal springs of the United States and other countries of the world; a summary 2. A brief history of spa therapy 3. Healing Sources SPAs and Wellbeing From the Baltic to the Black Sea. 4. Taking the Waters: Spirit, Art, Sensuality. 5. National Roman Museum, Baths of Diocletian 6. Nagayu Onsen, Ōita: A Sparkling Bathing Experience in Kyūshū’s Fizziest Waters 7. Two Cases of Ulcerated Breast Cancer Treated with Carbon Dioxide 8. A trial of the Bath Waters: the treatment of lead poisoning 9. Carbon Dioxide in Medicine 10. Did You Know That These Springs Around The World Have Naturally Carbonated Water That’s Even Safe For Drinking? 11. Royat Chamalières, a Belle Epoque spa in the heart of Auvergne 12. Mariánské Lázně - second-largest Bohemian spa town 13. Marianske Lazne, Czech Republic: This year at Marienbad, they're still taking the waters 14. Balneotherapy in Medicine: A Review 15. The Tissue Response to Hypoxia: How Therapeutic Carbon Dioxide Moves the Response toward Homeostasis and Away from Instability 16. Carbon dioxide Bath 17. CO2 Balneotherapy for Arterial Occlusion Diseases*: Physiology and Clinical Practice 18. Effects of repeated carbon dioxide-rich water bathing on core temperature, cutaneous blood flow and thermal sensation