1. 表示疾病的总称，为不可数名词。如：

Flies spread disease. 苍蝇能传播疾病。

Disease is usually caused by germs. 疾病多由病菌引起。

War and disease had thinned the population. 战争和疾病已使人口减少。

2. 用于身体部分连用，表示相应的病，通常不可数。如：

Some alcoholics develop liver disease. 有些酗酒者会得肝病。

Smoking is the prime cause of lung disease. 抽烟是得肺病的主要原因。

Tension is a major cause of heart disease. 精神紧张是引起心脏病的主要原因。

但有时也可连用不定冠词。如：

She has caught a lung disease. 她染上了肺部疾病。

She got a rare liver disease when she was only twenty. 他年仅20岁时就患上了一种罕见的肝病。

3. 表示某种疾病，为可数名词。如：

Cancer is a deadly disease. 癌症是一种致命的疾病。

Many cattle ape suffering from a disease called BSE. 许多牛得了疯牛病。

Why does man have more diseases than animals? 人类的疾病为什么比动物的多?

4. 有关“疾病”的表达习惯：

你生了什么病?

正：What’s your trouble?

误：What’s your disease?

假期中他害了一场大病。

正：While on holiday he caught a serious disease.

误：While on holiday he caught a big (heavy) disease.