It appeared from the literature that the most often occurring yellow dyestuffs in ancient textiles contain flavonoids. A research program for the separation of flavonoids was executed by means of thin-layer chromatography. Some hundreds of well-dated textile samples of the period 1500-1850 have been investigated. From the literature search it was expected that the analysis of yellow dyestuffs would give further clues for the establishing of the date of the textile object investigated. From the laboratory research, however, it appears that about 80% of all samples was dyed with Weld and that no further clues about the date can be expected by analysing yellow dyestuffs in ancient textiles.