When natural capsaicin, isolated from Capsicum annum, was exposed to Aspergillus niger in soybean dextrose media(SDM), two transformation products accumulated. These products were found to be phenolic compounds by diazotized sulfanilic acid test on a TLC plate. In order to isolate the main product of the two, a proper scale fermentation was carried out. One gm of capsaicin dissolved in a minimun amount of dimethylformamide was equally distributed into ten 2-liter flasks containing 500㎖ of SDM after 24 hours growth of A. niger, and fermentation was carried out for another 48 hours. The cultured broth was then extracted repeatedly with ethylacetate. The combined ethylacetate fraction(1500m1) was evaporated to dryness under reduced pressure. The residue was dissolved in ethylether and extracted with N-NaOH solution. After acidifying with hydrochloric acid the solution was reextracted with ethylether. The ethereal~residue(1.18g) was chromatographed over a silicic acid column and gradaent elution with benzene and ethylacetate was carried out. Fractions containing the main product was collected. The. yields were 360㎎(oil). The presence of vanillyl moiety was confirmed by UV absorption spectrum. When NMR signals of the product were compared with those of natural capsaicin, a new signal(τ6.5) corresponding to the two methylene protons of hydroxy methyl group appeared at expense of methyl protons of terminal isopropyl group(τ9.05). The oily product was derivatized to its acetate and purified through a small silica gel column. The presence of two kinds of different acetyl and tertiary methyl protons, and olefinic protons in the acetate was confirmed with their chemical shift values and coupling constants. However, integral values of tertiary methyl and olefinic protons were not agreeable. This kind of discrepancy was solved by assuming that the isolated transformation product is really a mixture of two compounds, traps-8-hydroxymethyl-N-vanillyl-6-nonenamide and traps-8-hydroxymethyl-N-vanillyl nonanamide. This assumption was substantiated by gas chromatographic data and also by comparison of NMR and IR spectra of natural capsaicin(mixture of capsaicin and dihydrocapsaicin) -and synthetic capsaicin.