The formulation of natural substances together with a biocompatible or biodegradable carrier material to form composites or encapsulates has a great relevance for pharmaceutical, cosmetic and food industries. Several precipitation methods with supercritical fluids can be successfully adapted to produce these materials. This article presents a review of the main aspects of supercritical encapsulation and co-precipitation processes, focused on a process mechanisms description as well as of the types of materials that can be formulated with them. (C) 2008 Elsevier B.V. All rights reserved.