The complex ecology of mould growth and mycotoxin production can produce mixtures of mycotoxins in foods and feeds, especially in cereals. The co-occurrence of mycotoxins can affect (Miller, 1991) both the level of mycotoxin production and the toxicity of the contaminated material. The production of the aflatoxins in stored grains, for example, may be enhanced by the presence of trichothecenes, whereas the toxicology of naturally occurring combinations of trichothecene mycotoxins is reportedly (Schiefer et al, 1986) determined by synergistic interactions, in experimental animals. For example, in a study with swine, the affect of deoxynivalenol on weight gain and feed conversion was synergized by T-2 toxin. Interactions involving non-toxic fungal metabolites have also been reported (Dowd, 1989), including the potent synergism of non-toxic F. graminearum metabolites (culmorin, dihydroxycalonectrin and sambucinol) with deoxynivalenol. To date, too little is known about this particularly important area of mycotoxicology.