Cytochrome P450 2C19 (CYP2C19) is an enzyme complex that plays a role in the metabolism of several drugs and is part of the super family of cytochrome P450. Genetic polymorphisms in these enzymes are associated with the emergence of poor metabolic phenotypes (poor metabolizers / PMs and intermediate metabolizers / IMs) that have a poor ability to metabolize the drugs that become substrates. Genotypes and phenotypes were analyzed using PCR-RFLP and bio-analysis of omeprazole levels in 30 subjects from ethnic Malay living in South Sumatra. Markers used to assess the presence of polymorphisms in the CYP2C19 gene are two polymorphic sites of exon 5 (CYP2C19 * 2) and exon 4 (CYP2C19 * 3). 321 bp DNA bands for exon 5 and 271 bp for exon 4 will be...