Abstract: AIM To modify the structure of gastrodin using cell suspension cultures of Platycodon grandiflorum as biocatalyst. METHODS Using plant tissue and cell culture techniques to establish cell suspension cultures, and chromatographic and spectral techniques to isolate and identify the product. RESULTS 1) The medium of MS + 5.0 mg·L^-1 NAA was good for the induction and growth of the callus cultures, and that of MS + 0.5 mg·L^-1 NAA + 0.5 mg·L^-1 6-BA + 0.2 mg·L^-1 2,4-D for the growth of suspended cell cultures. 2) Gastrodin was bioconverted to P-hydroxy-methyl-phenol, the deglucosylderivative, in good yield by cell suspension cultures of Platycodon grandiflorum. CONCLUSION Biotransformation using plant cell suspension cultures is an approach to structural modification of some natural products.