CO₂ Therapy: Maria's Gas

What CO₂ therapy and Maria's Gas are

Natural carbon dioxide (CO₂) of volcanic origin rises from the bedrock around Mariánské Lázně (Marienbad), traditionally known as Maria's Gas. It emerges from the Maria Spring in the town centre, has a CO₂ content of 99.7% and is one of the four natural healing resources of Marienbad, alongside the mineral springs, peat and the healing climate.

The spa uses it in three procedures: the dry gas bath, the carbonated mineral bath and gas injections. All three rest on the fact that carbon dioxide passes through the skin and acts above all on the small vessels of the skin and subcutaneous tissue. Which of them a patient receives, and how many, is decided by the spa physician at the initial examination.

The therapeutic use of natural CO₂ in Marienbad goes back to the 19th century, when local physicians began giving carbonated baths; subcutaneous application of the gas developed in the 20th century.

How the individual procedures work

1. Dry CO₂ gas bath (the Marienbad gas wrap)

The patient lies in a sealed bag reaching to the neck or applied to part of the body; the bag is filled with natural gas, which is absorbed through the skin. The procedure usually lasts 20–30 minutes and is taken lying down, at rest. During it most guests notice a sensation of warmth and slight tingling of the skin, a sign that the skin vessels have widened. Nothing special is needed for the procedure — only comfortable clothing and time for a short rest afterwards.

2. Carbonated mineral bath

A bath in mineral water in which natural CO₂ bubbles. The water is 33–34 °C, cooler than an ordinary warm bath; thanks to the gas acting on the skin vessels, the patient nevertheless perceives it as warm. The bath usually lasts 20 minutes, and fine bubbles form on the skin during it. It is followed by a rest lying down, which is part of the procedure. A detailed overview of what has been published on carbonated baths can be found in the article CO₂ baths: what the science says.

3. CO₂ gas injections (insufflation)

A physician or trained nurse uses a fine needle to apply a small amount of natural CO₂ under the skin — most often around the large joints, along the spine or in the lower limbs. The sites and their number are chosen by the physician according to the diagnosis. During the application the patient feels slight pressure or a "bubbling" under the skin, which subsides within moments; the gas is absorbed and the patient can carry on with the day's programme. The procedure is described in detail in the article CO₂ gas injections.

4. Maria's gas bath with oxygen therapy

The newest of the treatments combines two that already exist here: the dry gas bath in Maria's gas and oxygen therapy. It runs like the dry gas bath, except that the guest breathes enriched oxygen during it. Whether the combination suits you is decided by the spa physician at the initial examination, as with every other treatment.

How long a course lasts

CO₂ procedures are prescribed as a course: as a rule several times a week for the whole stay, often combined with other procedures (peloids, therapeutic exercise, the drinking cure). The number of procedures and their frequency are set by the spa physician, who may adjust them during the stay.

The length of the stay is governed not by the procedure but by the item of the Czech indication list you arrive with. For hypertension of the second to third degree (II/3), for example, the basic stay is 28 days in comprehensive care or 21 days in contributory care; for arterial disease of the limbs (II/4) it is 21 days in both types of care. Self-paying guests choose the length in consultation with the spa physician.

Which conditions it is used for

CO₂ procedures are not a separate item of the Czech indication list; they are procedures the spa physician builds into the treatment plan for the diagnosis the patient arrives with. In the Czech indication list they are among the basic procedures for diseases of the circulatory system (indication group II):

On the basis of long spa practice the physician also prescribes them for diseases of the musculoskeletal system (indication group VII) — above all gas injections around painful joints and along the spine — and in the after-care of chronic wounds as a supplement to the care led by the treating doctor. A complete overview of diagnoses is on the indications and contraindications page.

When CO₂ therapy is not suitable

The general contraindications of spa rehabilitation care under the indication list apply, among others:

• all diseases in the acute stage and conditions in which a deterioration of health can be expected;
• clinical signs of circulatory failure, malignant arrhythmias and persistent hypertension above 120 mm Hg diastolic pressure;
• conditions within 3 months of deep vein thrombosis and within 6 weeks of the resolution of superficial thrombophlebitis;
• recurrent profuse bleeding in the past 12 months;
• infectious diseases transmissible from person to person;
• pregnancy.

Gas injections are additionally not given where there is acute inflammation or a skin disease at the injection site, or in severe blood-clotting disorders. The complete list of contraindications is on the indications and contraindications page.

Who decides on inclusion

Whether any CO₂ procedure is included in the treatment plan, and of which kind, in what number and at what frequency, is decided by the spa physician after the initial examination; for patients with hypertension or arterial disease, in cooperation with their treating doctor. CO₂ therapy supplements the treatment a patient already has; it does not replace it. If you notice unusual complaints during the course, tell the spa physician — the plan can be adjusted.

What a patient can realistically expect

A review of CO₂ balneotherapy in cardiovascular disease summarises three measurable effects of the carbonated bath: increased skin blood flow, a slight drop in body temperature and a sensation of warmth (Pagourelias et al., 2011, Int J Biometeorol). What controlled studies have documented beyond that:

• Skin blood flow and walking in arterial disease of the lower limbs. In a randomised crossover trial in 18 patients with peripheral arterial disease of the lower limbs, immersing the feet in carbonated water raised laser-measured skin blood flow by 300% and tissue oxygen by 10%; in plain water the flow did not change (Hartmann et al., 1997, Angiology). In a follow-up randomised trial in 24 patients with claudication, a four-week course of foot baths (five times a week, 30 minutes) increased both tissue oxygen and the distance patients could walk without pain (Hartmann et al., 1997, Angiology). Both studies used artificially carbonated water and had small samples.
• Blood pressure. In a randomised trial in 70 women aged 48–60 with climacteric syndrome, mean daytime systolic pressure fell by 13.7% after ten dry CO₂ baths (Chekhoeva et al., 2024, Bull Rehabil Med). The control group received no treatment and this was a specific group of women; the result therefore cannot be transferred to all patients with hypertension.
• Healing of chronic wounds. In a double-blind randomised trial of 57 chronic diabetic wounds, 20 of 30 wounds healed after 20 applications of CO₂ gas to the skin, and none in the air-treated control group (Macura et al., 2020, Int Wound J). This was gas applied to the skin, a method close to the dry gas bath, not a water bath or injections; the sample was small.

For the musculoskeletal system and for gas injections, CO₂ procedures are used on the basis of long spa practice as part of a broader programme drawn up by the spa physician. How the procedures affect you is assessed by the physician during your stay.

Practical information

CO₂ procedures are available at the Ensana spa hotels in Marienbad; carbonated baths, for example, are among the main procedures at the Centrální Lázně hotel. They form part of comprehensive and contributory spa stays as well as self-paid treatment programmes. For guests insured in the Czech Republic, comprehensive care covers treatment, accommodation and meals, while contributory care covers the treatment only; in both cases the procedures prescribed by the spa physician form part of the covered treatment. Details are in the guide to spa treatment and insurance.

Frequently asked questions about CO₂ therapy

What is "Maria's Gas"?

Maria's Gas is natural carbon dioxide of volcanic origin with a purity of 99.7%, which rises from the Maria Spring in the centre of Marienbad. It is one of the town's four natural healing resources and is used in dry gas baths, carbonated baths and gas injections.

What happens during a dry gas bath — and does it hurt?

You lie for 20 to 30 minutes in a bag filled with natural CO₂, which is absorbed through the skin. The procedure is painless; most guests feel warmth and a gentle tingling of the skin.

Which conditions is CO₂ therapy used for?

Above all for diseases of the circulatory system in indication group II — hypertension, arterial disease of the limbs and functional disorders of the peripheral vessels — and, on the basis of spa practice, also for diseases of the musculoskeletal system and in the after-care of chronic wounds. The spa physician decides on inclusion.

How many procedures are needed?

The number of procedures and their frequency are set by the spa physician; they are usually prescribed several times a week for the whole stay. The length of a covered stay is determined by the item of the Czech indication list — for hypertension II/3, for example, the basic stay is 28 days in comprehensive or 21 days in contributory care.

Are there contraindications?

Yes. CO₂ procedures are not given, among other cases, for diseases in the acute stage, with signs of circulatory failure, after a recent thrombosis and in pregnancy; gas injections are additionally not given where there is inflammation or a skin disease at the injection site or a clotting disorder. An initial medical examination always takes place before the cure begins.

Where can I book CO₂ therapy?

At the Ensana spa hotels in Marienbad as part of a treatment stay. All three forms — dry gas baths, carbonated baths and gas injections — are offered by the Ensana Nové Lázně hotel.