Resins significantly improved the production of trichothecenes from Myrothecium by a method which may be useful for the production of antibiotics in submerged cultures.M. verrucaria CL-72 is a good producer of macrocyclic trichothecenes, particularly verrucarin A.The resins evaluated were the Amberlite resins XAD-4, XAD-7, XAD-8, and Amberchrom CG-71 and CG-161.The latter 2 are resins which are of a finer mesh size than the Amberlite resins.The resins were 1st evaluated for their ability to adsorb the trichothecenes from the aqueous fermentation broth.Both XAD-4 and CG-71 were relatively inefficient at adsorbing the more polar trichothecenes (e.g. <60% of roridin A and baccharinoid B4 were adsorbed by these resins), but performed satisfactorily with the less polar trichothecenes such as verrucarin J (>80% absorption from solution).The other resins, XAD-7, XAD-8, and CG-161 adsorbed >80% of the trichothecenes from the fermentation broths, though XAD-8 tended to be somewhat less efficient.Therefore, XAD-7 and CG-161 (chromatog. grade of XAD-7) were the resins of choice.