硒是人体中不可缺少的微量元素.微者,极少之意,完全缺少或摄之过多,均可引起疾病,危害健康.硒能防病在我国东北、西北等部分地区,由于土壤和水里缺硒,这一带地区的羊羔和牛犊常患一种被称为“白肌病”的地方性心肌营养不良症,严重者可因呼吸困难而死亡.生活在这一带的人也常患与“白肌病”相近似的“克山病”,患者往往有心悸、头晕、气短、心力衰竭等症状,严重者常因心力衰竭而致死,而且死亡率相当高.检查这些病畜和人,发现他们体内的硒含量均很低.在七十年代,我国在病区进行了大面积口眼亚硒酸钠的试验观察,发现硒对防治“克山病”有一定效果. Selenium is an indispensable microelement in human body.Micro, minimal meaning, complete lack or too much, can cause disease, endanger the health.Selenium can prevent disease in some areas of northeast and northwest of our country, due to soil and There is a lack of selenium in the water, and lambs and calves in this area often suffer from endemic myocardial dystrophy known as “white muscle disease,” which can often be fatal due to dyspnoea. People living in this area are also often affected “Keshan disease” which is similar to “white muscle disease”, patients often have heart palpitations, dizziness, shortness of breath, heart failure and other symptoms, severe cases are often fatal due to heart failure, and the mortality rate is very high. Their body selenium content is very low in the seventies, our country in the ward conducted a large area of ​​oral sodium selenite test observation found that selenium on the prevention and treatment of “Keshan disease” have a certain effect.