Tagetes patula plants have been cultivated in field in large quantity to produce raw material as source of extracts containing thiophenes. The thiophene contents of seeds and plants both fresh and dried from 10 cultivar were analyzed. The adult plants derived from seeds with a total thiophene content lower than 100 g g-1 showed a similar low total thiophene content. The seeds with a high total thiophene content gave plants with the same qualitative and quantitative phytochemical results. The total thiophene content of the dried plants is nearly twice the yield from fresh material. However, considering the commercial needs which could require large amounts of vegetal raw, the extraction from dried material might be more useful. Above all, this work suggests also that, in order to obtain plants with high thiophene contents, an accurate selection of high thiophene containing seeds is necessary