This review focuses on the characterization of the thixotropic property, the factors affecting the thixotropic property and its pharmaceutical applications. These factors include pH, temperature, polymer concentrations, polymer modification, polymer combinations, and addition of cations or excipients. The relationships between the rheological properties of thixotropic formulations, and their effects on the controlled drug delivery through various routes including oral, topical, ophthalmic, dental and mucosal administration and pharmacological efficacies were also discussed. The comprehensive analysis of theological and mechanical properties will provide an insight into the potential usage of thixotropic formulations as drug delivery systems. (C) 2009 Elsevier B.V. All rights reserved.