The trolleybus loop and the canisters
The third instalment of A Doctor's Word begins with a memory. MUDr. Pavel Knára, emeritus chief physician of the Nové Lázně spa house, remembers the days when the trolleybus had its terminus and turning loop by the Forest Spring. Townspeople came with bottles and canisters and carried the Forest Spring home. But, as he writes in the hotel newspaper Marienbad News, there is a catch — and it concerns anyone who takes mineral water away from a spring.
Why mineral water is best drunk at the spring
Marienbad's springs contain iron. While the water is underground, the iron is ferrous. As soon as it reaches the air, it oxidises to ferric iron. MUDr. Knára likes to recall Antonín Somol, the former head of the local internal medicine department, who set no store at all by ferric iron. You can see it without a laboratory: water in a canister gradually turns cloudy and a rusty sediment settles at the bottom. That sediment is the ferric iron.
The authors of the book on Marienbad's mineral springs add a second point: cold water drunk straight from the spring contains the most carbon dioxide. Warming, shaking and standing all let it escape.
Hence the advice MUDr. Knára keeps giving his guests:
- Drink right at the spring. That is where the water has the composition for which the physician prescribed it.
- If you take water with you, close the bottle tightly and keep it in the fridge.
- Drink it by the next day at the latest. Do not store it for longer — the iron oxidises in the meantime.
The advice applies to all of Marienbad's springs, not just the Forest Spring. How prescribed drinking fits into your day is described in our drinking cure guide.
A spring with a long and surprising history
The Forest Spring was probably already in use at the end of the 17th century. The first documented capture and a simple thatched shelter date from 1827–1828, when Professor Steinmann from Prague also carried out the first analysis. In 1840 an octagonal pavilion carried on two rows of columns replaced the old shelter. Because the 1827 capture was in poor condition, a new one was made in 1869 — and with it a new colonnade designed by the Marienbad architect Friedrich Zickler. The capture was last reconstructed in 1905: since then the spring has been collected by a bell-shaped capture 6.9 metres below ground. The pavilion was originally open and could be walked through; it was glazed only in 1956.
An unexpected chapter followed in 1999. During work on the sewers the spring was contaminated with styrene, toluene and other harmful substances, and its use was banned. A replacement source of similar mineral water was sought nearby — which is how the borehole that now supplies the Josef Spring came about. According to the 2018 book, the Forest Spring is once again safe and suitable for normal use. The whole story of how the springs were captured is told in How the springs were captured.
What is in the Forest Spring
| Parameter | Forest Spring |
|---|---|
| Sodium (Na) | 549 mg/l |
| Bicarbonate (HCO₃) | 1,352 mg/l |
| Sulphate (SO₄) | 511 mg/l |
| Iron (Fe) | 9.9 mg/l |
| Total mineralisation | 2,752 mg/l |
| Free carbon dioxide | 2,960 mg/kg |
Complex analysis from 2014 and control analysis from 2017, as given in the book "Minerální prameny v Mariánských Lázních k pitné léčbě" (Bartoš, Nečasová, Knára, 2018).
Technically, it is a bicarbonate-sulphate sodium acidulous water — cold, hypotonic and strongly mineralised. Unlike the Rudolph Spring, sodium and bicarbonate dominate here; the Forest Spring, MUDr. Knára stresses, has plenty of both.
What the Forest Spring is traditionally used for
Ensana's 2025 medical catalogue lists the Forest Spring as a spring for the drinking cure and for inhalation. Traditionally it is used for upper respiratory and digestive conditions, and for some urological conditions such as uric acid stones. This is traditional use prescribed by a physician; whether the Forest Spring belongs in your treatment, and whether you drink it warm or cold, is the physician's decision.
Digestive, respiratory and urinary system disorders are among the indications for spa treatment in Marienbad. The overview is on the Indications and contraindications page, with more context in our articles on spa treatment for the respiratory tract and on digestive disorders.
Not for everyone. It is precisely the higher sodium and bicarbonate content that means the physician does not prescribe the Forest Spring to everyone: for people who need to limit salt, and with some types of urinary stones, another spring is chosen. The book's authors also remind readers that no mineral water, not even a medicinal one, is meant for permanent drinking. Decisions about the drinking cure and its dosage are made by the spa physician at your initial examination, not by this article.
Where to find the Forest Spring
The Forest Spring pavilion stands at the northern edge of the spa quarter by the Třebízský brook, at the end of a pleasant walk through the park. The location and a description of the spring are in the springs overview. A note on the pavilion: according to the town portal it is currently closed temporarily, while the original spring outlet remains freely accessible. Please check the current situation before you go. And when you set off, take your spa cup and drink on the spot — just as MUDr. Knára advises.
More from the A Doctor's Word series
- Rudolph Spring — the calcium and magnesium water
- Ambrose Spring — iron-rich water and the Goethe legend
- Forest Spring — why mineral water is best drunk at the spring (this article)
All the springs, and when the drinking cure is used in Marienbad, are covered on our Mineral springs page. The physicians who lead the spa's medical care today are introduced on the Medical team page.
We paraphrase MUDr. Pavel Knára's words from his column in the hotel newspaper Marienbad News 5/2024, published by the operator of the Ensana spa hotels (internal material). This article is not a substitute for medical advice; whether a drinking cure becomes part of your treatment plan, and its dosage, is decided by the spa physician.
