The time course of 3-acetyldeoxynivalenol (AcDON) formation was analysed over a 11 day culture period of Fusarium graminearum (DSMO 4258) on rice. The maximum of 2840 mg/kg AcDON was detected after 9 days of culture. To overcome the complicated clean up of the solid substrate extract, 10% methanol in water was applied as extract solvent. After liquid-liquid partition with ethyl acetate, more than 75% of the toxin could be detected. After one simple clean up step (column chromatography over florisil) AcDON could be crystallised. After ion exchange chromatography deoxynivalenol (DON) could be crystallised and an overall yield of 1,44 g DON per kg of culture was obtained.