Der iva t ives of the s y m m e t r i c a l t r i az ines can act as folic acid antagonis ts [19]. The abili ty of such antagonis ts to induce " thymine s tarvat ion" has been descr ibed [12]. A typical f ea tu re of folic acid def ic iency in the body is a d is turbance of nucleic acid me tabo l i sm [18]. Folic acid antagonis ts a re c lassed as exogenous et iological f ac to r s in the development of hypoplast ic and ap las t ic anemias [3]. Toxicoa l le rg ic ( immunoaggress ive) blood d i s ea se s a re included by the authors under the same heading. Fol ic acid av i taminos is is accompanied by g loss i t i s , s tomat i t i s , u lcera t ive gas t r i t i s , and enterocol i t i s [14].