The trichothecenes are a large family of chemically related mycotoxins. They are produced by various species of Fusarium, Myrothecium, Trichoderma/Podostroma, Trichothecium, Cephalosporium, Verticimonosporium, and Stachybotrys. Chemically, trichothecenes are a class of sesquiterpenes. The determining structural features causing the biological activity of trichothecenes are the 12,13-epoxy ring, the presence of hydroxyl or acetyl groups at appropriate positions on the trichothecene nucleus, and the structure and position of the side-chain. They are produced on many different grains such wheat, oats or maize by various Fusarium species including F. graminearum, F. sporotrichioides, F. poae and F. equiseti. Some molds that produce trichothecene mycotoxins, for example Stachybotrys chartarum, can grow in damp indoor environments. It has been found that macrocyclic trichothecenes produced by S. chartarum can become airborne and thus contribute to health problem for building occupants. A poisonous mushroom native to Japan and China, Podostroma cornu-damae, contains six trichothecenes, including satratoxin H, roridin E, and verrucarin. Classification General classification Trichothecenes are a group of over 150 chemically related mycotoxins. Each trichothecene displays a core structure consisting of a single six-membered ring containing a single oxygen atom, flanked by two carbon rings. This core ring structure contains an epoxide, or tricyclic ether, at the 12,13 carbon positions, as well as a double bond at the 9, 10 carbon positions. These two functional groups are primarily responsible for trichothecene ability to inhibit protein synthesis and incur general cytotoxic effects. Notably, this core structure is amphipathic, containing both polar and non polar parts. All trichothecenes are related through this common structure, but each trichothecene also has a unique substitution pattern of oxygen containing functional groups at possible sites on carbons 3,4,7,8, and 15. These functional groups govern the properties of an individual tricothecene and also serve as the basis for the most commonly used classification system for this family of toxins. This classification system breaks up the trichothecene family into four groups: Type A, B, C, and D. Type A tricothecenes have hydroxyl, ester, or no functional group substitutions around the core ring structure. Common examples of these are Neosolaniol with a hydroxyl substitution at carbon 8, and T-2 toxin with an ester substitution at carbon 8. Type B tricothecenes are classified by the presence of carbonyl functional groups substituted around the core ring structure. Common examples of these include nivalenol and trichotecin, which both have a ketone functional group at carbon 8. Type C trichothecenes