Eudysmic ratio

The eudysmic ratio (also spelled eudismic ratio) is a term commonly found in the fields of pharmacology, chemistry, and molecular biology which describes the difference in pharmacologic activity between the two enantiomers of a drug.

In pharmacology it is frequently, though not always, the case that one enantiomer of a chiral drug has greater pharmacological activity than the other. The eudysmic ratio is a mathematical equation that quantitatively measures the difference in this activity. A eudysmic ratio significantly differing from 1 means that there is a difference in activity between the two enantiomers.