The spa town of Kyselka (literally meaning "Acidulous Mineral Water Spring" is located approximately 11 kilometres northeast of Karlovy Vary in a narrow woody valley of the Ohře River at an elevation of 340 metres above sea level. The name Buková kyselka (Beech Acidulous Mineral Water Spring) is first mentioned in the second edition of Dr. W. Payer's work on balneology written in 1522. In the 1790’s, Buková kyselka was already well-known and the acidulous water was bottled in earthenware jugs and distributed on an irregular basis. The visit of King Otto of Greece in 1852 was a more than welcome event promoting the small spa. The main thermal spring was named Otto Spring in His Majesty's honour and Carlsbad composer and conductor Josef Labitzký wrote a quadrille entitled "Memories of Kyselka".
The most respected medical authority and promoter of Kyselka in the 19th century was Dr. Josef Löschner, an outstanding balneologist. In 1867, the Otto Spring was leased out from Count of Neuberg by a Carlsbad mineral water exporter, Heinrich Mattoni. With unprecedented energy, he ventured into a grand-scale construction of the spa and in export of water from the Otto Spring. In Kyselka, he built a mineral water filling and shipping plant with residential buildings and warehouses. The building of spa houses, hotels, colonnades, and a hydropathic facility followed. Unfortunately, these buildings are currently facing continuous dilapidation. Mattoni also invested in capturing new springs. In 1894, he constructed a railway track connecting Vojkovice nad Ohří and Kyselka. In the 1880’s, Mattoni's mineral water belonged among the world's most famous mineral waters and it has retained its excellent reputation to the present day.
One of the oldest and historically most valuable quarters of Kyselka, known as Radošov, is located approximately one kilometre from the town. Radošov was probably founded in the 12th century on a junction of a trading trail leading across the Ohře River. It is first mentioned in a deed dating to 1226. Ancient settlement in the area is supported by fortified structures on the nearby hills of Košťál and Thebisberg where strongholds were standing since prehistoric times. Their existence is documented by massive walls and numerous archaeological findings from the Late Bronze Age. A roofed wooden bridge across the Ohře River stood in Radošov for many centuries. It was built upon the order of Emperor Charles IV at the site of Radovan' Ford in 1364. The historical bridge was renewed in 2003 after being destroyed by a fire in 1986.
Other points of interest include the originally Gothic Church of St. Wenceslaus, an old cross of conciliation on the left bank of the Ohře, and the site of Jindřich Spring. A cloister of the Sisters of the Holy Cross with an infant home had been in Radošov until World War II, the premises of which currently serve as the local basic school. Civic amenities in Kyselka include a police station, a kindergarten, a post office, a medical facility, a library, and a cinema.