The influence of naturally occurring phenolic compounds, isolated from common spice plants: carnosol, rosmanol (7a-), epirosmanol (7b-) from rosemary (Rosmarinus officialis L.); rosemaric acid from rosemary and oregano (Oreganum vulgare L.); capsicin and dihydrocapsicin, hot-tasting compounds, from hot pepper (Capsicinum annuum L.); ferulic acid amide of tyramine from black pepper (Piper nigrum L.); piperin-related compound from thyme (Thymus serpyllum L.); apigenin and apiin from parsley (Petroselinum crispum) as inhibitors of the formation of 1,4-pyrazine cation free radicals in the Maillard reaction between D()-glucose and 2-,3-and 4-aminobutanoic acid, respectively, have been studied by electron spin resonance (ESR) spectroscopy. The effect of phenolic compounds, constituents of spice plants, on mutagenic and carcinogenic heterocyclic amines which are end-products of the Maillard reaction in the presence of creatinine, have been studied by high pressure liquid chromatography (HPLC). All investigated compounds showed strong inhibitions effects on pyrazine cation free radical formation, precursors in the formation of 2-amino-3,4,8-trimethylimidazo(4,5-f)quinoxaline, as well as effects of antimutagenicity and anticarcinogenicity.