This article examines laboratory methods that are used or may be used to monitor newly developed heparins, low-dose vitamin K antagonists, new thrombin inhibitors such as recombinant hirudin, and oligopeptide thrombin inhibitors (some of which it is hoped will be orally active), thromboxane receptor antagonists, glycoprotein IIb-IIIa inhibitors, and ticlopidine-like structures.