the environmental contaminants which have their major effects on the small intestine may be classified into five major categories : ( 1 ) bacterial , viral , and parasitic agents , ( 2 ) food and plant substances , ( 3 ) environmental and industrial products , ( 4 ) pharmaceutical agents , and ( 5 ) toxic agents whose metabolic effects are dependent on interreaction with intestinal bacterial flora , other physical agents ( detergents ) , human intestinal enzyme deficiency states , and the nutritional state of the host .
C0021852
small
C0021853
intestinal