Dyscrasia (from Greek "Dyskrasia", meaning bad mixture), in Ancient Greek medicine,(This word is given in Aphorism 79 or Organon of Medicine by Dr. Samuel Hahnemann.) is the imbalance of the four humours (blood, black bile, yellow bile, and water(phlegm)) which were believed to exist in the body, and were believed to be the direct cause of all disease. This is similar to the Asian concept of Yin and Yang; it was believed that imbalance of the two polarities caused ailment.
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. 1
Antimetabolitic Agents such as Leucovorin, Methotrexate, etc. may cause blood dyscrasias.
- 1. Stedman's medical dictionary, 6th edition