放射能泉

At least 8.25 Mache units (111 Bq/kg) of radon. The dose is very small and inhaled radon is exhaled again within hours. Misasa and Masutomi are the best-known examples. Used for gout and high uric acid, and sometimes billed as 万病の湯 — "water for every ailment" — a claim to treat as folklore rather than medicine.

What it is like

Colourless, odourless, and indistinguishable by feel from plain hot water. This is the one class you cannot detect with your senses at all — only the 温泉分析書 on the wall will tell you.

Indications (適応症)

High uric acid (gout), rheumatoid arthritis, ankylosing spondylitis

Contraindications (禁忌症)

Usually avoided during pregnancy as a precaution. In enclosed inhalation rooms, observe the posted time limits.

適応症 and 禁忌症 are the claims a certificate is permitted to state under the Hot Spring Act. They are not medical advice, and nothing here is. If you have a heart condition, are pregnant, or are unwell, ask a doctor rather than a guidebook.