Fungi of the genus Alternaria are commonly parasitic on plants and other organic materials. Many are in fact plant pathogens of field crops whereas others infect foodstuffs after harvest (1). They can grow at low temperatures and so may cause spoilage of fruits and vegetables during refrigerated transport and storage. Alternaria alternata is a frequently occurring species of particular interest to mycotoxicologists because it produces a number of mycotoxins, including alternariol (AOH; 3,7,9-trihydroxy-1-methyl-6H-dibenzo[b,d]pyran-6-one; Fig. 1), alternariol monomethyl ether (AME; 3,7-dihydroxy-9-methoxy-1-methyl-6H-dibenzo[b,d]pyran-6-one; Fig. 1), altertoxins I, II, and III [1S-(1α, 12aβ, 12bα)] 1,2, 11, 12, 12a, 12b-hexahydro-1,4,9,12a-tetrahydroxy-3,10-perylenedione;[7aR-(7aα,8aα,8b α, 8cα)]-7a,8a,8b,8c,9,10-hexahydro-1,6,8c-trihydroxyperylo[1,2-b]oxirene-7,11-dione; and [laR-(laα,lbβ,5aα,6aα,6bβ,10aα)]-la,1b,5a,6a,6b,10a-hexahydro-4,9-dihydroxyperylo[1,2- b:7,8-b’]bisoxirene-5,10-dione; respectively, andL-tenuazonic acid [5S-[5R*(R*)]]-3-acetyl-5-(1-methylpropyl)-2,4-pyrrolidinedione (1–5). Isolation of AOH and AME was first reported in 1953 (2). A culture of A. alternata on corn flour has been found to be carcinogenic in rats, and culture extracts were mutagenic in various microbial and cell systems (6–8). A. alternata might be one of the etiological factors for human esophageal cancer in Linxian, China (8). AOH, AME and, in particular, the altertoxins are mutagenic (1,7,9–13). Although no long term cancer studies of these mycotoxins in laboratory animals have been carried out, there are reports of subcutaneous induction of squamous cell carcinoma in mice by human embryoesophageal tissue treated with AOH and of subcutaneous tumorigenicity with NIH/3T3 cells transformed by AME (9, 14).