A Doctor's Word: the Rudolph Spring, Marienbad's calcium and magnesium water
The first instalment of our series A Doctor's Word: emeritus chief physician MUDr. Pavel Knára on Marienbad's best-known spring. Where the Rudolph Spring got its name, what it contains, what it is traditionally prescribed for in the drinking cure — and where you can drink it.
A series in which the doctor speaks
Marienbad lives by its springs, and nobody knows them better than the physicians who have prescribed them for decades. That is why we are starting a series called A Doctor's Word. Our guide is MUDr. Pavel Knára, emeritus chief physician of the Nové Lázně spa house. He has worked in Marienbad's spa houses since 1976 and co-wrote a specialist book on the drinking cure with the local springs. In the hotel newspaper Marienbad News he regularly writes a short column about one spring; we retell his thoughts here in our own words and add facts from the book. You can meet the people who lead the medical team today on our Medical team page.
The first instalment belongs to a spring Marienbad would be unthinkable without: the Rudolph Spring, which locals and regulars fondly call "Rudolfka".
A meadow spring named after a crown prince
Where the Rudolph Spring pavilion stands today, the so-called Meadow Spring once rose in the fields of the farmers of Úšovice. The Teplá monastery wanted it for years. It was first analysed in 1820 and recommended for use, but the farmers refused to give up their land. Only in 1865 did the monastery manage to buy the neighbouring plot; the capture followed, and in the summer of 1867 the spring was named Kronprinz-Rudolfsquelle, the Spring of Crown Prince Rudolph.
A simple glazed pavilion stood over it at first. In 1902 the capture was deepened to four metres and the pavilion rebuilt; in 1937 a borehole at least ten metres deep followed, so that the mineral water would not mix with ordinary groundwater from the brook's floodplain. Further outlets were captured nearby — Rudolph I and II in 1902, Rudolph III in 1910. According to the book, the water bottled today under the name Rudolph Spring comes from the nearby boreholes BJ-36 and BJ-37. How the other springs were captured is told in How the springs were captured.
MUDr. Knára adds that the 20th century was, in Marienbad, the era of the Rudolph Spring: it was this spring that made the town the place people travel to with kidney and urinary tract complaints.
What is in the Rudolph Spring
MUDr. Knára sums up what makes Rudolfka special in three phrases: plenty of calcium, plenty of magnesium and little sodium. The figures from the latest analysis in the book bear this out:
| Parameter | Rudolph Spring |
|---|---|
| Calcium (Ca) | 266 mg/l |
| Magnesium (Mg) | 133 mg/l |
| Sodium (Na) | 85.8 mg/l |
| Bicarbonate (HCO₃) | 1,590 mg/l |
| Total mineralisation | 2,246 mg/l |
| Free carbon dioxide | 2,600 mg/kg |
Control analysis from 2017 (borehole BJ-37), as given in the book "Minerální prameny v Mariánských Lázních k pitné léčbě" (Bartoš, Nečasová, Knára, 2018). The composition of a natural spring can change slightly over time.
Technically, it is a bicarbonate calcium-magnesium ferruginous acidulous water — cold, hypotonic and strongly mineralised. Calcium and magnesium are roughly in a 2 : 1 ratio. According to the book, one spa cup (220 ml) contains around 60 mg of calcium, 30 mg of magnesium and 20 mg of sodium.
MUDr. Knára regards the low sodium content as one of Rudolfka's great strengths. Sodium holds water in the body, he reminds readers, which is why people with heart and circulatory conditions and many older people are advised to watch it in both food and drink. It is also why Marienbad's springs are not interchangeable: some contain many times more sodium.
What the Rudolph Spring is traditionally used for
The Rudolph Spring is Marienbad's best-known mineral water and has always been associated with the kidneys and urinary tract. Ensana's 2025 medical catalogue lists it as a spring prescribed in the drinking cure for kidney and urinary tract disorders, and as a complement to osteoporosis treatment. This is traditional use within a drinking cure prescribed by a physician, not a treatment in its own right.
Urinary system disorders — such as chronic and recurrent inflammation of the kidneys and urinary tract, or kidney stones without urinary congestion — are among the indications for spa treatment in Marienbad. The full overview is on the Indications and contraindications page; how the drinking cure fits into the wider treatment is described in our article on kidney and urinary tract treatment.
Not for everyone. The book's authors point out that, because of its high calcium content, the Rudolph Spring is not prescribed in larger amounts to people with certain calcium-containing kidney stones or increased calcium excretion in the urine; the physician then chooses a spring with less calcium, such as the Ambrose Spring or the Caroline Spring. They also recall a rule that applies to all springs: no mineral water, not even a medicinal one, is meant for permanent drinking.
Which spring you drink, how much, at what temperature and at what time of day is set by the spa physician at your initial examination and adjusted during your stay. Decisions about the drinking cure and its dosage are theirs, not this article's. Our drinking cure guide describes how a cure usually runs.
Where to drink Rudolfka
According to MUDr. Knára, you will find it all year round in the drinking pavilion of the Cross Spring on the Main Colonnade. In season it also flows at the small drinking fountain by the Rudolph Spring pavilion in Úšovice and at the Small Colonnade of the Caroline Spring, opposite the Centrální Lázně hotel. The location and a description of the spring are in the springs overview.
Drink slowly, in small sips, ideally from a spa cup — and right at the spring. Why that matters is explained by MUDr. Knára in the third instalment of the series, on the Forest Spring.
More from the A Doctor's Word series
- Rudolph Spring — the calcium and magnesium water (this article)
- Ambrose Spring — iron-rich water and the Goethe legend
- Forest Spring — why mineral water is best drunk at the spring
All the springs, and when the drinking cure is used in Marienbad, are covered on our Mineral springs page.
We paraphrase MUDr. Pavel Knára's words from his column in the hotel newspaper Marienbad News 4/2023, 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.
Sources
Studies and official documents this article relies on. Our content does not replace medical advice.
- Bartoš J., Nečasová D., Knára P.: Minerální prameny v Mariánských Lázních k pitné léčbě (Mineral springs in Mariánské Lázně for the drinking cure). FORNICA graphics, 2018, ISBN 978-80-87194-54-6 — History of how the Rudolph Spring was captured, its classification and the analysis table (control analysis 2017, borehole BJ-37), the ion content of one spa cup, and the note on whom the spring is not prescribed to in larger amounts.
- Marienbad News 4/2023 — column "A Doctor's Word: the Rudolph Spring" (MUDr. Pavel Knára), Czech edition — Hotel newspaper of Ensana Health Spa Hotels, internal material of the operator. We paraphrase the physician's words; health statements from the column are used only as traditional use.
- Medical catalogue of Ensana Health Spa Hotels Mariánské Lázně 2025 — mineral springs for the drinking cure — Internal material of the operator: the Rudolph Spring is prescribed in the drinking cure for kidney and urinary tract disorders and as a complement to osteoporosis treatment; the drinking cure is always set by the treating physician.
- Indications and contraindications for spa treatment in Marienbad — Overview of the conditions treated in Marienbad, including urinary system disorders, and of the general contraindications.
What concerns you?
More articles
A Doctor's Word: the Forest Spring, and why mineral water is best drunk at the source
The third instalment of A Doctor's Word: MUDr. Pavel Knára remembers the trolleybus turning loop by the Forest Spring and explains why Marienbad's mineral waters are best drunk fresh at the fountain — and what to do if you take some away in a bottle.
A Doctor's Word: the Ambrose Spring, iron-rich water and the spring of love
The second instalment of A Doctor's Word: MUDr. Pavel Knára on one of the town's oldest springs. Three iron-bearing outlets, two centuries of capture, traditional use in the drinking cure — and the legend of Goethe and Ulrike that earned it the name spring of love.
Drinking Cure in Marienbad — A Guide to the Mineral Springs
How to drink mineral water properly in Mariánské Lázně (Marienbad) — the main springs, their composition and traditional use, the usual course of a day, what research says about the drinking cure, and practical advice for your stay.
