Objective: The aim of this study was to investigate the effect of polycyclic aromatic hydrocarbons (PAHs) in rectal carcinoma and hepatocarcinoma genesis. Methods: The PAHs in the human rectal cancer and liver cancer tissues, the adjacent tissues and homologous tissues without rectal cancer or liver cancer were extracted by ultrasonic wave. The extracts were then cleaned up and enriched by solid phase extraction, analyzed by high performance liquid chromatography (HPLC) with fluorescence spectroscopy. Results: Four kinds of PAHs were detected in human rectal and hepatic tissues. The contents of pyrene, 2-methylanthracene and benzo (a) pyrene in both rectal cancer tissues and adjacent homologous tissues were higher than rectal tissues without rectal cancer, the differences were statistically significant (P < 0.05). The contents of phenanthrene in the three kind of tissue were not significant (P > 0.05). The differences of the content of each PAHs between rectal cancer and adjacent tissue were not significant (P > 0.05). The contents of the four PAHs in the three kinds of liver tissues were not statistically significant (P > 0.05). Conclusion: PAHs are found in human rectal tissues or hepatic tissues. The contents of PAHs in human rectal tissue may have an effect on the occurrence of human rectal cancer while the contents of PAHs in human hepatic tissues may have not ones. Objective: The aim of this study was to investigate the effect of polycyclic aromatic hydrocarbons (PAHs) in rectal carcinoma and hepatocarcinoma genesis. Methods: The PAHs in the human rectal cancer and liver cancer tissues, the adjacent tissues and homologous tissues without rectal cancer or The extracts were then cleaned up and enriched by solid phase extraction, analyzed by high performance liquid chromatography (HPLC) with fluorescence spectroscopy. Results: Four kinds of PAHs were detected in human rectal and hepatic tissues. The contents of pyrene, 2-methylanthracene and benzo (a) pyrene in both rectal cancer tissues and adjacent homologous tissues were higher than rectal tissues without rectal cancer, the differences were significantly (P <0.05). The contents of phenanthrene in the three kind of tissues were not significant (P> 0.05). The differences of the content of each PAHs between rectal cancer and adjacent tissu The contents of the four PAHs in the three kinds of liver tissues were not statistically significant (P> 0.05). Conclusion: PAHs are found in human rectal tissues or hepatic tissues. The contents of PAHs in human rectal tissue may have an effect on the occurrence of human rectal cancer while the contents of PAHs in human hepatic tissues may have not ones.