Cosmetic oil of Guevina avellana mol is industrially extracted by cold pressing, producing a residual meal with 10-12% on dry base of oil, which spoils, limiting its application for human consumption. An enzymic pre-treatment was incorporated into the conventional oil extraction process by cold pressing, with the purpose of improving the oil yield and the residual meal quality. The effect of enzyme/substrate ratio, temperature and moisture was analysed during hydrolysis using two commercial enzyme mixtures. Pressing conditions during this stage were also studied. An increase in extracted oil was obtained for both enzymic mixtures. The best result was a yield up to 98% of extracted oil and residual meal with 1.5% of oil. An oil extraction yield up to 98% and a residual meal with 1.5% of oil. This result was further validated in an industrial plant scale. (C) 2002 Elsevier Science Ltd. All rights reserved.