Salsobromoiodic thermal waters: what they are, benefits, and where to find them in Italy

Water that tastes of ancient seas: an introduction to salsobromoiodic thermal baths

There is a moment in the thermal baths when the body stops resisting. The water does its work in silence, with that slowness that belongs to profound things. But not all thermal waters are the same, and among the many classifications that hydrological science has developed over time, that of salsobromoiodic waters occupies a very particular place, both for the richness of their chemical composition and for the singular geological history that generated them.

To define them simply as “salt waters” would be reductive. They are in fact the result of millions of years of stratification, of vanished seas and evaporitic rocks that have retained an extraordinary mineral heritage in the subsoil. In the regions of the Po Valley, along the Adriatic coast, and in some areas of the Apennines, these waters still emerge today with chemical characteristics that modern thermal medicine recognizes as clinically relevant.

Salsobromoiodic waters: the chemical composition that defines them

To be classified as salsobromoiodic, a thermal mineral water must satisfy precise criteria established by Italian legislation (Presidential Decree of 23 July 1998 and subsequent amendments) and by medical hydrological tradition. The name itself describes the composition: sals- refers to sodium chloride (salt), bromo indicates the presence of bromides, iodo refers to iodides.

In analytical terms, water is defined as saline when the sodium chloride content exceeds 2 g/L, brominated when bromides exceed 1 mg/L, and iodinated when iodides exceed 1 mg/L. Waters that simultaneously satisfy all three of these conditions fall into the salsobromoiodic category, which represents one of the richest and most therapeutically active among hydromineral classifications.

The total mineralization of these waters is generally very high, often exceeding 10 g/L, and in some cases reaches concentrations comparable to seawater or even higher. It is precisely this characteristic that determines their therapeutic uses and clearly distinguishes them from oligomineral waters or bicarbonate-calcium waters, which act on completely different physiological mechanisms.

Geological origin: why Italy is so rich in these waters

The presence of salsobromoiodic waters in Italy is closely linked to the geology of the Po-Adriatic basin. During the Mesozoic and Cenozoic eras, vast inland seas occupied the area that today corresponds to the Po Valley and the Upper Adriatic. When these basins dried up, the dissolved mineral salts deposited in the sedimentary rocks, forming the so-called evaporitic deposits, layers rich in halides and sulfates.

Meteoric waters, infiltrating into the subsoil through fissures and fractures, pass over time through these layers and progressively become enriched with chlorides, bromides, and iodides. The presence of overlapping impermeable layers means that these waters remain confined at depth, often under high pressure conditions, and reach significant temperatures before rising to the surface through artesian wells or natural springs.

This is why the main thermal resorts with salsobromoiodic waters are concentrated in the provinces of Ferrara, Bologna, Forlì-Cesena, Ravenna, Parma, and in some areas of the Marche: a geographical arc that faithfully follows the ancient profile of the vanished seas.

Differences from other thermal waters: why classification matters

The panorama of Italian thermal waters is extraordinarily varied. Alongside salsobromoiodic waters there are sulfurous waters, bicarbonate-calcium waters, chloride-sulfate waters, radioactive waters, arsenical waters, and many other categories, each with specific therapeutic indications and distinct mechanisms of action. Understanding the differences helps in choosing the thermal destination most suited to one’s needs.

Sulfurous waters, typical of Saturnia or the Campi Flegrei, are rich in hydrogen sulfide and have a specific action on the respiratory tract, joints, and skin. Bicarbonate-calcium waters, like many waters of the Alpine and Apennine arc, act mainly on the digestive system and metabolism. Salsobromoiodic waters, on the other hand, have a broader and more articulated action profile, which makes them indicated for a greater number of pathologies and disorders.

A further distinction concerns the internal subcategories of the salsobromoiodic classification itself. Based on the prevalence of certain ions, these waters can be further defined as hyperthermal (temperature above 37°C), isothermal (around 37°C), or hypothermal (below 20°C). Temperature, combined with composition, determines the methods of use and the intensity of physiopathological effects.

The benefits of salsobromoiodic waters: what thermal medicine says

Italian thermal medicine, regulated by the Ministry of Health, recognizes salsobromoiodic waters as therapeutically effective for a wide spectrum of clinical indications. The available scientific evidence, although still partly under investigation in the literature, supports the use of these waters in various fields.

Respiratory and otorhinolaryngological system

The inhalation of aerosols and nebulization of salsobromoiodic waters represent one of the most established therapeutic uses. Iodine, absorbed by transepithelial or inhalation route, exerts an antiseptic, mucolytic, and anti-inflammatory action on the mucous membranes of the upper and lower airways. The main indications include chronic sinusitis, rhinitis, pharyngitis, chronic bronchitis, seromucosal otitis, and laryngitis. Bromine, for its part, has a sedative effect on irritated mucous membranes and helps reduce hypersecretion.

Musculoskeletal system

Baths in salsobromoiodic water produce analgesic and anti-inflammatory effects that find application in the treatment of osteoarthritis, rheumatoid arthritis in non-acute phase, ankylosing spondylitis, fibromyalgia, and chronic pain states. The mechanism of action is multifactorial: hydrostatic pressure reduces joint load, heat improves local circulation and promotes muscle relaxation, while dissolved minerals contribute to modulation of the inflammatory response.

Gynecological system

Vaginal irrigations with salsobromoiodic waters are indicated in chronic inflammation of the female genital system, in leukorrhea, and in some disorders associated with menopause. Iodine plays an important role in the balance of thyroid function, and its local action is associated with antiseptic and trophic properties on the mucous membranes.

Skin and circulatory system

Prolonged immersion in waters with high saline concentration produces an osmotic effect that stimulates cutaneous microcirculation and promotes edema reduction. Some indications concern psoriasis, chronic dermatitis, and venous insufficiency of the lower limbs. Sodium chloride, at therapeutic concentrations, has a keratoplastic action and normalizes the cellular turnover of the epidermis.

How salsobromoiodic waters are used: techniques and treatments

Contrary to what one might think, the use of salsobromoiodic waters is not limited to immersion in a pool. Balneotherapy is only one of the modalities provided by therapeutic protocols recognized by the National Health Service, which includes a range of applications differentiated by purpose and technique.

Balneotherapy involves partial or total immersion in tubs or pools with thermal water, at temperatures varying between 36 and 39°C, for sessions of 15-20 minutes. Mud therapies, very widespread in the resorts of Ferrara and Ravenna, combine the action of salsobromoiodic water with that of mature thermal mud, namely mud in which colonies of algae and microorganisms have developed that further enrich the biologically active component.

Inhalations and aerosols represent the approach of choice for respiratory pathologies: water is nebulized into particles of varying sizes that penetrate to different depths in the airways. Nasal irrigations, nasal showers, and tubal insufflations complete the therapeutic armamentarium for the otorhinolaryngological sphere. Vaginal irrigations and salpingoclysis are instead the specific techniques for gynecological indications.

It is important to emphasize that therapeutic cycles recognized by the NHS provide for a defined number of applications (generally 12 per cycle) and require medical prescription. Wellness treatments, of a non-therapeutic but preventive and regenerative nature, follow less rigid protocols and are accessible even without specific clinical indication.

Where salsobromoiodic waters are found in Italy: the main thermal resorts

The geographical distribution of salsobromoiodic thermal baths in Italy follows, as anticipated, the geology of the Po-Adriatic basin, with some extensions in central Italy. Below is a map of the main destinations, with specification of the water category and peculiar characteristics of each.

Salsomaggiore Terme (Parma, Emilia-Romagna)

Salsomaggiore Terme is probably the most famous of the Italian salsobromoiodic thermal resorts. Its waters belong to the sodium salsobromoiodic category, with a sodium chloride concentration that can exceed 40 g/L, a bromide content of around 100-120 mg/L, and iodides between 3 and 5 mg/L. The temperature of the spring waters is approximately 26-28°C. The city owes its historical fortune precisely to these waters, already exploited in the nineteenth century for rheumatological and dermatological treatment. The thermal baths are indicated mainly for rheumatic, gynecological, and dermatological diseases.

Cervia (Ravenna, Emilia-Romagna)

The thermal baths of Cervia draw from water classified as hypersaline salsobromoiodic, with characteristics very similar to seawater but with an even higher mineral concentration. The sodium chloride content exceeds 50 g/L, while bromides and iodides are present in therapeutically significant concentrations. The proximity to the salt pans of Cervia is not coincidental: the same geology that allowed the formation of these salt pans is responsible for the presence of such rich waters at depth. The main indications concern the respiratory tract, rheumatology, and dermatology.

Terme di Riolo and Ferrara-Ravenna area

The thermal area that includes Riolo Terme, the thermal baths of the Romagna Apennines, and the deep springs of Ferrara expresses waters of variable composition: some are classified as sulfate salsobromoiodic, with the additional presence of sulfates in significant concentrations, others fall into the pure salsobromoiodic category. Riolo Terme, in particular, boasts waters with specific properties for the digestive system and rheumatology, with a bicarbonate-sulfate component that accompanies the salsobromoiodic matrix.

Terme della Versilia and northern Tuscan area

Some springs in Versilia and Garfagnana present waters with salsobromoiodic components, although usually less concentrated than the Po Valley resorts. In these cases, one often speaks of oligomineral waters with bromoiodic traces, namely low-mineralization waters that nevertheless contain bromides and iodides in sufficient quantities for inhalation therapies. The prevalent indications concern diseases of the respiratory tract and pediatric disorders of the upper airways.

Terme di Senigallia and Adriatic Marche area

Along the Adriatic coast of the Marche, particularly in the area of Senigallia and in the deep springs of the Metauro, waters classifiable as salsobromoiodic emerge, as proof of the geological continuity of the Adriatic basin. Concentrations are generally less elevated than in the Emilia-Romagna resorts, but the characteristics remain adequate for balneotherapy treatments and inhalations. The therapeutic profile is similar: rheumatology, respiratory tract, gynecology.

Terme di Acireale and volcanic areas of eastern Sicily

In eastern Sicily, near Acireale, some thermal springs present chloride-bromide waters with traces of iodine, deriving from the interaction of groundwater with marine deposits and the volcanic formations of Etna. These waters, classified as sodium chloride bromoiodic, find their main use in balneotherapy and inhalation therapies, with spring temperatures often exceeding 30°C.

Terme di Sirmione (Brescia, Lombardy)

Sirmione is one of the most unique cases in Italian thermalism for at least two reasons. The first is geological: the thermal springs gush directly from the bed of Lake Garda through a fissure in the limestone rock of the lacustrine peninsula, making this outcrop unique within the European hydrothermal landscape. The second is the chemical classification of the water, which distinguishes it from most of the resorts described in this article: it is classified as sulfurous salt-bromine-iodic, a dual category that incorporates both sulfurous and salt-bromine-iodic components within the same source. The water contains hydrogen sulfide, sodium chloride, iodine, and bromine, and is hyperthermal, emerging at approximately 69°C.

This composite profile determines a dual mechanism of action: sulfur exerts its mucolytic, vasodilating, and immunostimulating action, while iodine and bromine act with anti-inflammatory, antiseptic, and sedative effects. The thermal mud of Sirmione, matured in outdoor tanks with spring water, is enriched by a particular prokaryote, the Cyanobacterium Aponinum, whose biological activity enhances the anti-inflammatory effect of the mud itself, with ongoing scientific research conducted with the support of the Scientific Committee internal to the establishment. The main indications include respiratory and ENT tract, rheumatology, dermatology, and gynecology.

Porretta Terme (Alto Reno Terme, Bologna, Emilia-Romagna)

Porretta Terme, now part of the municipality of Alto Reno Terme in the Bolognese Apennines, is one of Italy’s oldest spa resorts: the first evidence of the therapeutic use of its waters dates back to the pre-Roman era, and as early as 1576, the physician Giovanni Zecchi performed its first scientific classification. The case of Porretta is particularly instructive because, similar to Castrocaro, the area is home to two chemically distinct families of springs that emerge a short distance from each other. The Salt-Bromine-Iodic Springs Group includes mesothermal waters (average temperature 35-36°C) with high salinity and a fixed residue at 180°C of approximately 5,285 mg/L, classified as sodium-chloride salt-bromine-iodic. The Sulfurous Springs Group, on the other hand, includes hypothermal waters (average temperature 24°C) with a clinically significant hydrogen sulfide content, classified as sulfurous.

Despite the different therapeutic composition, ionic analyses show that both groups share the same sodium chloride base, differing in the presence or absence of the sulfurous component and in the different saline concentration. The total flow of the salsobromoiodic springs is approximately 223 liters per minute. The Castanea establishment, where all therapeutic services including pool, mud, inhalations, and baths are provided, uses both groups of waters for differentiated indications: salsobromoiodic for rheumatology, gynecology, and circulation, sulfurous mainly for the respiratory tract.

Castrocaro Terme (Forlì-Cesena, Emilia-Romagna)

Castrocaro Terme is one of the most important salsobromoiodic resorts in Italy, with a history intertwined with one of the most fascinating scientific discoveries of Italian thermalism. In 1830 the chemist Antonio Targioni Tozzetti analyzed the waters of a local spring, identifying for the first time the simultaneous presence of bromine and iodine, effectively opening the modern era of salsobromoiodic crenotherapy. The water is classified as cold salsobromoiodic: it gushes at ambient temperature from layers of porous rock called “spungone” at depths between 70 and 150 meters, with a fixed residue at 180°C exceeding 40 g/L, an iodine content of 25.7 mg/L, and bromides around 98 mg/L. It is visually distinguished by its intense green color, due to the presence of natural microalgae of the genus Chlorella. The establishment also uses sulfurous waters from distinct springs, making it one of the few Italian resorts to offer both types in a single facility. The main indications concern rheumatology, respiratory tract, gynecology, venous circulation, and dermatology.

Monticelli Terme (Parma, Emilia-Romagna)

The Terme di Monticelli were born in 1927 from an accidental discovery: Italo Borrini, a farmer from Parma, drilled the ground in search of water to irrigate his fields and, at approximately 64 meters depth, intercepted a powerful salsobromoiodic spring. The waters of Monticelli are among the most concentrated in the entire Italian thermal panorama: official analytical data report bromides at 360 mg/L, iodides at 40.8 mg/L, and a sodium chloride concentration three times higher than seawater, with sodium exceeding 26,000 mg/L and chloride exceeding 70,000 mg/L. The classification is hypersaline salsobromoiodic. The establishment also has sulfurous waters for inhalation treatments, and the four indoor pools are heated to temperatures between 30 and 34°C. The high percentage of bromides gives these waters a marked sedative and anti-stress effect, an element that also distinguishes them in terms of the subjective experience of the thermal bath. The main indications include rheumatology, respiratory tract, gynecology, and venous circulation disorders.

Abano Terme and Montegrotto Terme (Padua, Veneto)

The Euganean thermal basin, which includes Abano Terme, Montegrotto Terme, Galzignano, and Battaglia, is the largest salsobromoiodic area in Europe by facilities and volume of treatments. The waters are classified as hyperthermal sodium chloride salsobromoiodic, with a fixed residue at 180°C of 5-6 g/L, and gush from wells at temperatures reaching 87°C. Their origin is completely different from the Emilian Po Valley resorts: studies by the University of Padua and the Pietro d’Abano Thermal Studies Center have established that the waters infiltrate as rain on the Lessini Mountains in the Venetian Prealps, at approximately 2,000 meters altitude, travel about 80-100 kilometers through limestone rocks in the subsoil to depths of 2,000-3,000 meters where they reach temperatures of 200°C, and then rise to the surface after a journey estimated to last 25-30 years, becoming enriched with sodium, potassium, magnesium, iodine, and silicon. They do not derive from marine evaporitic deposits but from the dissolution of salts from carbonate rocks during the long hydrothermal circulation. Euganean mud, matured in tanks for at least 60 days with thermal water, has obtained a European patent for its anti-inflammatory efficacy. The main indications are rheumatology, orthopedic rehabilitation, and respiratory tract.

Tabiano Terme (Parma, Emilia-Romagna): sulfurous thermal baths, not salsobromoiodic

Tabiano deserves explicit clarification, as it is often associated with Salsomaggiore (they are about 5 km apart and share the same management company), yet the waters of these two spa resorts belong to completely different chemical categories. Tabiano’s waters are not salt-bromine-iodic: they are classified as sulfurous-sulfate-calcium-magnesic, with a fixed residue at 180°C of 3,660 mg/L and a hydrogen sulfide content reaching 175 mg/L, compared to the minimum classification threshold of 1 mg/L for sulfurous waters. This is one of the highest H2S concentrations in Europe. These are cold waters of meteoric origin, formed by the leaching of Messinian carbonate rocks. The mechanism of action is profoundly different: sulfur is mucolytic, antioxidant, antiseptic, and immunostimulating, and it acts primarily on the respiratory mucosa and the skin.

The indications of Tabiano are therefore almost exclusively otorhinolaryngological and respiratory (chronic bronchitis, sinusitis, seromucosal otitis) and dermatological. Those planning a stay in the area can understand Salsomaggiore and Tabiano as two complementary therapeutic products: one indicated for rheumatology, gynecology, and high saline mineralization, the other for the respiratory sphere and its chronic pathologies.

Terme Stufe di Nerone (Bacoli, Naples, Campania)

The Terme Stufe di Nerone, in the Phlegraean Fields in Bacoli, is the Italian salt-bromine-iodic resort with the longest documented history: the site was already active as a thermal facility in Roman times, visited by scholars and emperors who mentioned it in classical writings. The waters are classified as hyperthermal alkaline-earth sulfate salt-bromine-iodic, with springs emerging at temperatures between 74 and 80°C. Compared to the resorts in the Po Valley, the composition is enriched with a significant sulfate component and trace elements such as lithium, strontium, and fluorine. The geological origin is entirely distinct: the waters derive from the hydrothermal activity of the Phlegraean Fields volcanic system, which heats groundwater in contact with the magmatic rocks of the Phlegraean subsoil, where coastal marine salt deposits are also present.

A unique feature is antrum therapy, namely exposure to thermal vapors in the natural volcanic caves of the park, a microclimate saturated with mineral vapor that acts directly on the respiratory tract. In recent years the center has initiated collaborations with the University of Naples and with the Thermal Research and Studies Center to evaluate the effectiveness of these treatments on chronic pathologies and post-viral outcomes. The main indications include rheumatology, respiratory tract, dermatology, and rehabilitation.

Contraindications and precautions: when salsobromoiodic waters are not suitable

As with any therapeutic treatment, balneotherapy and inhalation treatments with salsobromoiodic waters are not without contraindications. The high mineralization of these waters requires a preliminary medical evaluation, especially in certain patient categories.

The main absolute contraindications include hyperthyroidism and active thyroid pathologies (due to the high iodine content), heart failure and uncontrolled arterial hypertension (due to the effect of balneotherapy on the cardiovascular system), severe renal insufficiency, neoplasms in active phase, severe exudative dermatitis, and acute infectious diseases. In pregnancy, use is not recommended without explicit medical advice.

An often underestimated precaution concerns the intake of thyroid hormones: patients on replacement therapy with levothyroxine who undergo intensive inhalation treatments with iodinated waters should inform their endocrinologist, as the additional iodine intake could require an adjustment of the pharmacological dosage.

How to choose the right salsobromoiodic thermal destination: practical advice

The choice among the various thermal resorts with salsobromoiodic waters depends on a series of factors that go well beyond simple geographical proximity. The mineral concentration of the water, the temperature of the spring, the availability of specific therapeutic techniques, and the level of services offered are all elements to consider.

For those seeking medical therapy recognized and reimbursable by the NHS, it is essential to consult a general practitioner or a specialist in medical hydrology to obtain the prescription and identify the most suitable affiliated facility. For those instead oriented toward a wellness and preventive approach, the choice may fall on resorts and establishments that offer broader experiences, integrating the quality of the water with wellness pathways, aesthetic treatments, and integrated tourism proposals.

Salsomaggiore Terme, with its Art Nouveau architecture and consolidated historical tradition, remains the reference destination for those seeking total immersion in Italian thermal culture. Cervia offers the added value of proximity to the sea and a territory rich in naturalistic attractions. The Romagna thermal baths of the Apennines instead combine treatment with the discovery of a hinterland still little frequented by mass tourism.

A heritage still to be discovered

Italian salsobromoiodic waters are a geological, cultural, and therapeutic heritage that international tourism still knows far too little about. While the sulfurous baths of Tuscany or the thermal waters of South Tyrol have gained global visibility, the circuit of salsobromoiodic spas in the Po Valley and the Adriatic remains largely a destination for connoisseurs—for those who can distinguish genuine therapy from a simple wellness experience and seek something more than a moment of relaxation in the water.

At a time when preventive medicine and integrated wellness occupy a growing space on the agenda of millions, these ancient waters still have much to say.
They are well worth listening to.

FAQ – Questions about salsobromoiodic thermal waters

Editorial notes

All clinical and therapeutic information contained in this article is for informational purposes and does not replace medical advice. References to therapeutic indications are based on the guidelines of the Italian Ministry of Health and official medical hydrology classifications (Presidential Decree of July 23, 1998). A preliminary medical evaluation is recommended for any thermal treatment.