The study of epigenetics explores the heritable modifications in gene regulation that take place without changes to the DNA sequence, providing an essential connection between environmental factors and heredity. Noncoding RNAs, histone modifications, and DNA methylation are important processes that control gene expression by altering chromatin structure and gene accessibility. Histone changes such as acetylation and methylation control the activation or repression of genes, whereas DNA methylation, usually at CpG sites, can silence genes. Noncoding RNAs regulate gene expression by influencing chromatin complexes. Epigenetic mechanisms are crucial for normal cellular functions including embryonic development, cell differentiation, and genome stability. Interference in any of these epigenetic regulations will lead to various diseases. Moreover, environmental factors including, stress, toxins, nutrition, and exposure to chemicals significantly impact the epigenome causing heritable changes in the genome. The intricacy of gene regulation and its effects on health and disease are greatly elucidated by our expanding knowledge of epigenetic mechanisms. This information forms the basis for developing novel therapeutic approaches, such as epigenetic medications, which provide viable means of reversing abnormal gene expression and reestablishing regular cellular activity in complex diseases.