Mofettes in Romania: what a mofette is, how a session works and where to find them, from Covasna to Tușnad

What is a mofette

A mofette is a vent of gases through cracks in the earth's crust, typical of areas with extinct volcanoes, such as the Harghita Mountains and the Ciomatu massif. The gas is almost entirely carbon dioxide; at Sântimbru-Băi the proportion is about 99%, with a little hydrogen sulphide. Hotel Tușnad, which has a mofette in its treatment centre, explains that the gas has no colour, smell or taste and can be felt only through its effect on the skin: the skin turns red and you feel a sensation of warmth.

The smell of rotten eggs in some places comes from the hydrogen sulphide, not from the carbon dioxide. This is also where the place names come from: Büdös, "the stinking one", at Sântimbru-Băi, and Mount Puturosu above Băile Bálványos.

The word is also used for the building put up over the vent: a room in which the gas collects low down and which you enter as you would a bath. Mofettes often lie next to springs of naturally sparkling mineral water, and the resorts that have them use both.

Where the mofettes in Romania are

The mofettes on this site are in seven resorts: six in the Székely Land, in Covasna and Harghita counties, and one in Bukovina, at Vatra Dornei. The table shows who runs each mofette and whether you need a doctor, because that changes how you use it. All the resorts are also in the pillar guide to thermal baths.

The mofettes of Covasna: hotels, hospital, Bardócz

At Covasna, the gas and the naturally sparkling waters shaped the resort's profile: it is Romania's resort dedicated to heart and circulatory diseases. The mofettes are in the treatment centres of the Căprioara, Covasna and Cerbul hotels, which you enter after a consultation with the balneology doctor, and in the "Dr. Benedek Géza" Cardiovascular Rehabilitation Hospital, where the resort's page describes the largest mofette ever built, 100 square metres, for a hundred patients at a time. You can only get into the hospital as a patient, with a referral.

The oldest is the Bardócz mofette, opened in 1882 in the yard of a house, with wooden rooms on whose walls patients have been writing their names for more than a century. It is private and has no published prices; the 2017 opening hours need to be confirmed by phone.

In the central park, the Devil's Pond (Balta Dracului) bubbles because of the same gas, but it is not a mofette: it is a muddy spring under a grille, which you look at from the edge.

Covasna

Covasna, CVOpenFree

Resorts and thermal baths

The mofette at Băile Tușnad

At Băile Tușnad, the mofette stands in a building in the forest. According to the resort's local council, you cross the bridge over the Olt next to Lake Ciucaș, take the road on the left, past the campsite and a mineral water spring, and climb through the forest to the building; from there the forest road continues towards the Falcon Rock reserve (Stânca Șoimilor) and returns to the bridge, in a loop.

The gas is used for dry baths, only on a doctor's recommendation. The Hotel Tușnad treatment centre provides the mofette only after a consultation with the balneology doctor and by appointment; it is paid separately, in the hotels' packages or with a treatment referral. The same town also has Wellness Tușnad, with a thermal water pool, but there is no mofette there.

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Băile Tușnad

Băile Tușnad, HROpenFree

Resorts and thermal baths

The mofettes of Bálványos and Puturoasă Cave

At Băile Bálványos, on Mount Puturosu, the gas comes out in several places. The fitted-out mofettes belong to the operators in the resort, each with its own hours and prices, and are used only on a doctor's recommendation, because gas baths have contraindications.

The rest are open-air vents, on the trail marked with a blue dot: Puturoasă Cave (Smelly Cave of Torja), an old sulphur mine gallery with yellow walls, the Killer Cave, the Birds' Cemetery and the Bufnitor peat bog, where the gas comes out in bubbles. They are not treatment sites. In Puturoasă Cave the gas sits about 1 m above the ground at the entrance and rises almost to the ceiling further in, and the back of the gallery is closed off with a grille: do not go past it and do not bend below the yellow sulphur line, which shows how high the gas reaches.

Băile Bálványos

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Resorts and thermal baths

Puturoasă Cave (Smelly Cave of Torja)

Turia, CV

Caves

Mofettes in Harghita: Harghita-Băi, Sântimbru-Băi, Seiche

• Harghita-Băi, about 21 km from Miercurea Ciuc: the resort grew up around the springs and mofettes; the warm bath was closed down in 1950, the mofette remained. It is open only in the warm season, roughly from May to November, and the baths are taken according to the posted rules.
• Sântimbru-Băi, about 22 km from Miercurea Ciuc, above 1,200 m: the mofettes were fitted out in the early 1960s and have the most concentrated gas in the Harghita range, according to the county's tourism portal. They are run by the local council, with free access, but without an authorised treatment centre and without medical staff; the instructions are posted at the mofette.
• Băile Seiche, 4 km from Odorheiu Secuiesc: the mofette and the fenced-off area around it have been closed since July 2026 because of gas and water leaks whose origin is still unclear. The springs, the Székely gates and Orbán Balázs's grave can be visited freely.

Harghita-Băi

Harghita-Băi, HROpenFree

Ski slopes

Sântimbru-Băi

Sântimbru-Băi, HROpenFree

Resorts and thermal baths

Băile Seiche

Odorheiu Secuiesc, HROpenFree

Resorts and thermal baths

The mofette at Vatra Dornei

Vatra Dornei is the only resort on this site with a mofette outside the Székely Land. The natural mofette is in the Bradul–Călimani centre, the resort's largest treatment centre, alongside carbonated baths and peat wraps from Poiana Stampei; it is also used by guests of Hotel Carol.

Treatments are given on working days, after a consultation with the doctor, by appointment at the hotel reception. You pay in full or with a treatment voucher from the Pensions Office (Casa de Pensii).

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Vatra Dornei

Vatra Dornei, SVOpenFree

Ski slopes

Borsec, Slănic-Moldova, Malnaș-Băi: is there a mofette?

"Borsec mofette" and "Slănic-Moldova mofette" are searched for often, but the Borsec and Slănic-Moldova pages mention no mofette: both are resorts of naturally sparkling mineral waters, which you drink from the spring or use for baths. The same goes for Malnaș-Băi, near Sfântu Gheorghe, and Buziaș Spa Resort, in the Banat. If you want a mofette in the Borsec area, the nearest one on this site is at Harghita-Băi.

Two other places with gas coming from the ground are not mofettes. Focul Viu (Living Fire) of Andreiașu de Jos, in Vrancea, is methane that burns by itself, and the Berca Mud Volcanoes in Buzău are cold mud pushed to the surface by gases, mostly methane. Neither is a treatment site.

How a mofette session works

In a treatment centre, the session begins with a consultation with the balneology doctor: at Covasna, Băile Tușnad and Vatra Dornei it is compulsory, and at Turism Covasna even guests staying there who have not come for treatment can try the mofette only after a consultation and on the doctor's recommendation.

You enter the mofette following the staff's instructions. You stand up, with your head above the layer of gas, for only a few minutes. A balneology doctor quoted by Știrile ProTV describes the procedure in authorised centres: the nurse goes in before the patients and measures the gas level, and the gas must be absorbed through the skin, not inhaled. The skin turns red and you feel warmth; Hotel Tușnad warns that carbon dioxide poisoning sets in fairly quickly, with headaches, dizziness and nausea.

How many sessions you have and how long each lasts is decided by the doctor. The price of a session is on the resort's page, where a published price exists.

Is a mofette dangerous? The safety rules

Yes, if you breathe in the gas. Carbon dioxide in high concentration is dangerous, and below the level at which it collects it can kill; that is why the back of Puturoasă Cave is closed off with a grille. The rules published by the operators and on the resort pages:

• Do not go in without the staff's instructions or, where there are no staff, without reading the posted instructions.
• Stand up, with your head up. Do not bend over, do not sit down and do not lower yourself into the layer of gas.
• Children and animals stay away. The gas is heavier than air and collects low down, at their height.
• Take the contraindications into account. Hotel Tușnad lists them: cancer, ulcerative diseases, heart failure, advanced atherosclerosis, pulmonary tuberculosis, epilepsy, the first 6 months after a heart attack or major heart surgery.

The difference between an authorised mofette and one with free access matters. The director of the National Institute of Balneology explained to Știrile ProTV that authorised mofettes have gas sensors and ventilation openings, while at unauthorised ones the gas level is measured empirically, with a flame. In September 2026, one man died and another ended up in intensive care after they were poisoned by carbon dioxide in a mofette at Sântimbru-Băi, a council-owned enclosure not authorised as a treatment centre.

Mofette benefits and indications, per the operators

The operators publish indications, not promises of a cure. Covasna and Băile Tușnad have a cardiovascular profile, and Hotel Tușnad explains the effect through the dilation of blood vessels, useful for people with poor arterial circulation. Băile Bálványos is also for cardiovascular conditions, Vatra Dornei for cardiovascular conditions and rheumatism, while for Sântimbru-Băi the page lists rheumatic and locomotor conditions.

All the operators require a doctor's recommendation, because the mofette has contraindications. Which resort to choose for which condition, with the types of water and treatment vouchers, is in the guide to spa resorts; where to bathe in warm thermal water, in the pillar guide to thermal baths.

Frequently asked questions

What is a mofette?

A natural vent of gas made up almost entirely of carbon dioxide, in areas with extinct volcanoes. The name is also used for the room built over it, where gas baths are taken, standing up, with your head above the layer.

Where are there mofettes in Romania?

On this site: Covasna and Băile Bálványos (Covasna county), Băile Tușnad, Harghita-Băi, Sântimbru-Băi and Băile Seiche (Harghita) and Vatra Dornei (Suceava). The mofette at Băile Seiche has been closed since July 2026.

Is a mofette dangerous?

Yes, if you breathe in the gas: carbon dioxide in high concentration is dangerous. Stand up, with your head above the layer, for only a few minutes, following the staff's instructions, and keep children and animals away, because the gas collects low down.

How long do you stay in a mofette?

Only a few minutes, according to the Covasna resort page; the exact duration and the number of sessions are decided by the balneology doctor at the treatment centre.

Do you need a doctor's recommendation for a mofette?

In the treatment centres at Covasna, Băile Tușnad and Vatra Dornei, yes: the mofette is used only after a consultation with the doctor. At Sântimbru-Băi access is free, but there are no medical staff, and the enclosure is not authorised as a treatment centre.

Who should not use a mofette?

Hotel Tușnad lists as contraindications cancer, ulcerative diseases, heart failure, advanced atherosclerosis, pulmonary tuberculosis, epilepsy and the first 6 months after a heart attack or major heart surgery. The decision is the doctor's.

Are mofettes open in winter?

The treatment centres at Covasna and Vatra Dornei give treatments all year. The mofette at Harghita-Băi is open only in the warm season, roughly May – November, and the Bardócz mofette in Covasna from 1 March to 1 November (hours published in 2017).

Does Borsec have a mofette?

The resort's page does not mention a mofette: Borsec is known for its springs of naturally sparkling mineral water. The same goes for Slănic-Moldova. The nearest mofette to Borsec on this site is at Harghita-Băi.

Is the mofette at Băile Seiche open?

No. The mofette and the fenced-off area around it have been closed since July 2026 because of gas and water leaks, and access is forbidden (situation on 5 November 2026).