Fuente: WIPO "essential oil or extracts" The invention relates to a process for processing twigs, foliage and similar plant parts for the extraction of essential oils (OE), in which a comminuted mass is subjected to a steam stream that is subsequently condensed for the extraction of an essential oil (EO) and a hydrolate (ID). The biomass (BM) is then subjected to a biodigestion phase for the production of methane and biogas; lignin and biographite are then extracted from the resulting biodigestate. The process of the invention allows a high degree of raw material reuse, reducing waste and achieving a high yield in biogas and lignin production.