Dyscrasia, is a concept from ancient Greek medicine with the word "dyskrasia", meaning bad mixture.

Ancient use

To the Greeks, it meant an imbalance of the four humors: blood, black bile, yellow bile, and water (phlegm). These humors were believed to exist in the body, and were the direct cause of all disease.

This is similar to the Asian concept of Yin and Yang that an imbalance of the two polarities caused ailment.

Modern use

It is still occasionally used in medical context for an unspecified disorder of the blood. Specifically it is defined in current medicine as a morbid general state resulting from the presence of abnormal material in the blood, usually applied to diseases affecting blood cells or platelets.

Antimetabolitic agents such as Leucovorin, Methotrexate, etc. may cause blood dyscrasias. Spironolactone (Potassium sparing diuretic), when used as a pro-drug to treat Conn syndrome may cause this side effect. Antiarrythmic drugs such as Tocainide, Phenytoin, and Mexiletine, also causes blood dyscrasis.

References