They are found in the main in North and South Phyongan Provinces, South Hwanghae Province, Kangwon Province and North Hamgyong Province.

The spas of Kim Jong Suk Sanatorium and Talchon Disabled Soldiers Sanatorium, Songchon Spa, Ongjin Spa, Sechon Spa, Pochonnaegok Spa and others contain radon in their water.

Radon spa is potent for the treatment of cardiovascular system disorders and nervous system disorders.

It is also efficacious for curing operation sequela, injury of muscles and skin and contracture after operation, chronic osteomyelitis, rheumatic arthritis, women's diseases, skin disorders and digestive system disorders.

The sulfuric spas in Sinchon, Paechon and other places are good for treatment of dermatosis.

The sulfuric spa produces good curative efficacy as the general action ingredients of the spa and the ions containing sulfur have direct influence upon the skin and respiratory mucosa and the absorbed sulfuric compounds work.

The chlorine-brine spas such as Phyongnam Spa, Unchon Spa and Yonan Spa No.2 are good for treatment of hypertension.

The chloride-brine spa is popular among hypertensives as it is helpful towards reducing blood pressure.

The sanatoria furnished with modern curative facilities and means have been built in the spa areas of the DPRK, which serve the working people for the improvement of their health and for the prevention and treatment of diseases.