(+)-Limonene was mixed in an artificial diet at a concentration of 1 mg/g of diet, and the diet was fed to the last instar larvae of common cutworm (Spodopteralitura). Metabolites were recovered from frass and analyzed spectroscopically. (+)-Limonene was transformed mainly to (+)-p-menth-1-ene-8,9-diol (uroterpenol) and (+)-p-mentha-1,8-dien-7-oic acid (perillic acid). Similarly, (-)-limonene was transformed mainly to (-)-p-menth-1-ene-8,9-diol (uroterpenol) and (-)-p-mentha-1,8-dien-7-oic acid (perillic acid). The results indicate that there is little difference in metabolic pathway between the (+)- and (-)-forms.