The use of supercritical fluid technology as an innovative technology to extract bioactive compounds has grown considerably in recent decades. Particularly, the recovery of antioxidants from different herbs is a matter of continuous research and development. Antioxidants can protect cells against the effects of free radicals and thus, play an important role in heart illness, cancer and other diseases. Rosemary (Rosmarinus officinalis L) has been recognized as one of the Lamiaceae plant with many important biological activities. Particularly, large antioxidant power has been recognized in rosemary and main substances related with this activity were the phenolic diterpenes such as carnosol, rosmanol, carnosic acid, methyl carnosate, and phenolic acids such as the rosmarinic and caffeic acids. Moreover, carnosic acid and carnosol are recognized as the most abundant antioxidants present in rosemary. In this work, supercritical fluid technology was applied to produce rosemary extracts with different compositions and thus, with different bioactivity properties. Selected extracts, from the variety of samples obtained, were used to study the capability of rosemary supercritical extracts to inhibit the proliferation of human liver carcinoma cells. These extracts showed a dose-dependent effect on inhibiting the proliferation of human hepatoma cells. Moreover, observed citostaticity appeared to be significantly influenced by their different composition, suggesting a relevant role of the technology to produce the extracts and the consequently obtained compositions on the potential antitumoral activity of rosemary. (C) 2012 Elsevier B.V. All rights reserved.