Abstract A new type of oil from Perilla frutescens, the piperitenone type, was discovered in Thailand. GC/MS analysis of steam-distilled oil showed that it contained piperitenone (36.3%) and limonene (23.7%). Crossing experiments between the piperitenone-type and the principal types of perilla suggested the presence of one dominant gene regarding the regulation of oil types between the piperitenone-type and the perillaldehyde-type.