Distribution and elimination of benz(a)anthracene (B(a)A), chrysene (Ch), and triphenylene (Tr) were compared after oral administration of the single compounds to 7-8-week-old female rats. These four-ring isomers were chosen because of their different carcinogenicity. The compounds have high affinity for lipid-rich tissues such as brain, mammary and parametrial adipose tissue. The relative availability of these compounds in the tissues examined decreased in the order Tr greater than B(a)A greater than Ch, but fecal elimination diminished in the opposite order Ch greater than B(a)A greater than Tr. Availability and fecal elimination of single polycyclic aromatic hydrocarbons (PAH) were influenced by the dose and concentration of PAH in the vehicle.