Protocols for the extraction of DNA from human blood and for genotyping for a number of common cytochrome P450 polymorphisms using either polymerase chain reaction (PCR)-restriction fragment length polymorphism or PCR-single-strand conformational polymorphism (SSCP) analysis are described. Rapid high-throughput techniques are also available for analyses of this type, but they require access to specialized equipment and are not considered here. General guidelines for performing amplification using PCR are described together with electrophoresis protocols for analysis of restriction digests of PCR products with agarose and polyacrylamide gels including the use of polyacrylamide-based gels for SSCP analysis. Protocols for the following specific isoforms and alleles are also provided: CYP1A1 (*2Band (*4alleles), CYP2C8 ((*3and (*4alleles), CYP2C9 ((*2, (*3, and (*11alleles), CYP2C19 ((*2and (*3alleles), CYP2D6 ((*3, (*4, (*5, and (*6alleles), CYP2E1 ((*5A, (*5B, and (*6alleles), and CYP3A5 ((*3allele).
