Initial results from high performance liquid chromatographic (HPLC) analysis of accelerated fluorescent tube-and mercury-incandescent lamp-aged mordanted wools dyed with old fustic, weld, quercitron bark, quercetin, dyer's greenweed and onion skins indicate that additional chromophoric and non-chromophoric compounds are generated upon photodegradation. Total amount recovered from dyed wools of quercetin (onion skins); luteolin and apigenin (both weld and dyer's greenweed); and genistein (dyer's greenweed) all increased upon accelerated ageing. Direct temperature mass spectrometry (MS) was successfully applied as a novel and promising technique for in situ dyed fibre analysis. Preliminary results for some of the accelerated light-aged wools above demonstrated its potential for studying changes in dye-fibre interaction upon ageing.