Increased yields of capsaicin and dihydrocapsaicin, major pungent principles of chilli pepper fruit, were obtained when immobilized placental tissues of Capsicum frutescens were treated with intermediate metabolites of the capsaicinoid pathway, i.e. l-phenylalanine, t-cinnamic acid, p-coumaric acid, caffeic acid, ferulic acid and vanillylamine in combination with l-valine. Although vanUlylamine and l-valine are the nearest precursors to capsaicin, their addition to immobilized placenta did not significantly affect the accumulation of capsaicin. Maximum capsaicin and dihydrocapsaicin accumulation was achieved on p-coumaric acid + l-valine treatment. Maximum percentage of bioconversion was observed in culture treated with t-cinnamic acid + l-valine. In nature, the ratio of the principle components — capsaicin and dihydrocapsaicin — is about 2∶1. In immobilized placental tissues fed with precursors, the ratio of capsaicin and dihydrocapsaicin varied between 2.2∶1 to 3.7∶1 compared with the ratio of 2:1 present in natural chilli pepper fruit. A productivity of 3.072 mg capsaicin/gDW/day was obtained by treating with p-coumaric acid + l-valine, which was 514% higher than that of chilli pepper fruit. These results successfully demonstrate the use of placental tissue, the site of synthesis of capsaicin, to enhance yields of metabolites in vitro using a combined precursor treatment.