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Most constituents were identified by gas chromatography by comparison of their retention indices with those in the literature or with those of available authentic compounds. The retention indices were determined in relation to a homologous series of n-alkanes (C6–C32) obtained under the same operating conditions. Further identification was made by comparison of their mass spectra with those stored in the library [14], peak enrichment on co-injection with authentic standard where possible as described previously [2–5]. The volatile compounds are displayed in Table 1, along with their percentages and retention indices calculated on a HP-5MS column. The hydrodistillation of C. tetragonum afforded yellow oils in yields of 0.53% and 0.21% (v/w, stem barks and leaves, respectively). The stem bark and leaf oils consist mainly of oxygenated monoterpene compounds (84.3% and 86.0%, respectively). The main constituents of the bark oil were cis-geraniol (65.1%) and geranyl acetate (14.8%). However, (E)-cinnamaldehyde (41.0%) and cis-geraniol (33.8%) were present in the leaf oil.