Folic acid, a form of vitamin B9, plays a critical role in various biological processes, including DNA synthesis and repair. Its role in cancer development and progression is complex, with conflicting evidence suggesting both protective and carcinogenic effects. Some studies indicate that folic acid may reduce cancer risk by promoting DNA methylation, enhancing DNA repair, and reducing oxidative stress. However, other studies suggest that high folic acid intake could promote cancer progression, particularly in individuals with pre-existing conditions or genetic mutations. The molecular mechanisms underlying these effects include folic acid's role in nucleotide synthesis, DNA methylation, homocysteine metabolism, and its interaction with cancer-related genes and receptors. Folic acid is involved in the synthesis of nucleotides, which are essential for DNA replication and repair. It also influences DNA methylation, an epigenetic process that can silence tumor suppressor genes and promote cancer. Additionally, folic acid acts as an antioxidant, reducing oxidative stress and DNA damage. However, excessive folic acid intake may lead to DNA hypomethylation, which can activate oncogenes and increase cancer risk. Folic acid also affects homocysteine levels, which are linked to various cancers. Furthermore, folic acid receptors (FR-α and FR-β) are overexpressed in several cancers, potentially facilitating cancer cell growth and progression. Despite its potential benefits, folic acid fortification has raised concerns about increased cancer risk, particularly in populations with high folic acid intake. Studies have shown associations between high folic acid levels and increased risks of certain cancers, including lung and prostate cancer. However, the evidence is conflicting, and more research is needed to clarify the relationship between folic acid and cancer. The review emphasizes the need for further pharmacogenomic studies and clinical trials to better understand the role of folic acid in cancer prevention and treatment. Overall, the relationship between folic acid and cancer is complex, and its impact may vary depending on individual factors, cancer type, and dosage.Folic acid, a form of vitamin B9, plays a critical role in various biological processes, including DNA synthesis and repair. Its role in cancer development and progression is complex, with conflicting evidence suggesting both protective and carcinogenic effects. Some studies indicate that folic acid may reduce cancer risk by promoting DNA methylation, enhancing DNA repair, and reducing oxidative stress. However, other studies suggest that high folic acid intake could promote cancer progression, particularly in individuals with pre-existing conditions or genetic mutations. The molecular mechanisms underlying these effects include folic acid's role in nucleotide synthesis, DNA methylation, homocysteine metabolism, and its interaction with cancer-related genes and receptors. Folic acid is involved in the synthesis of nucleotides, which are essential for DNA replication and repair. It also influences DNA methylation, an epigenetic process that can silence tumor suppressor genes and promote cancer. Additionally, folic acid acts as an antioxidant, reducing oxidative stress and DNA damage. However, excessive folic acid intake may lead to DNA hypomethylation, which can activate oncogenes and increase cancer risk. Folic acid also affects homocysteine levels, which are linked to various cancers. Furthermore, folic acid receptors (FR-α and FR-β) are overexpressed in several cancers, potentially facilitating cancer cell growth and progression. Despite its potential benefits, folic acid fortification has raised concerns about increased cancer risk, particularly in populations with high folic acid intake. Studies have shown associations between high folic acid levels and increased risks of certain cancers, including lung and prostate cancer. However, the evidence is conflicting, and more research is needed to clarify the relationship between folic acid and cancer. The review emphasizes the need for further pharmacogenomic studies and clinical trials to better understand the role of folic acid in cancer prevention and treatment. Overall, the relationship between folic acid and cancer is complex, and its impact may vary depending on individual factors, cancer type, and dosage.