During the last few decades, lipid nanocapsules have been receiving a lot of attention due to their unique properties, which not only make them efficient but also enable them to improve the effectiveness of drugs. A wide variety of diseases, including infectious, inflammatory, and cancerous diseases, can be treated with nanocapsules due to the physical protection they offer, their increased permeability to their targets, and their reduced side effects. This article is aimed at providing a comprehensive review of past studies on lipid nanocapsules and their applications in drug delivery and treatment of various diseases, as well as a comprehensive review of current interests in this field. Methods: Scientific data were collected by reviewing articles published in reliable databases such as PubMed, Scopus, and Google Scholar between ۲۰۱۰ and ۲۰۲۴. The study was conducted using keywords such as "lipid nanocapsules," "cancer," "drug delivery," "nanotechnology in medicine," "lipid-based drug carriers," and "target-based therapy" in order to carry out the research. To provide a comprehensive overview of lipid nanocapsules in drug delivery and disease treatment, a variety of articles were selected, focusing on laboratory and clinical studies. A total of ۵۰ articles were selected for review and analysis after they were refined and irrelevant ones were removed. Results: In the course of investigations, it was found that lipid nanocapsules were capable of carrying both hydrophilic and hydrophobic drugs as a consequence of their dual lipid-water structure. This feature has been used to treat cancer in particular. In a study conducted on doxorubicin, lipid nanocapsules were used to significantly enhance its targeting of cancer cells as well as reduce its toxicity in healthy tissues. Since lipid nanocapsules have the ability to cross physical barriers such as the blood-brain barrier, as well as a high level of biocompatibility, they have been successfully used to treat neurological diseases such as Alzheimer's disease and Parkinson's disease. A series of studies have shown that antiviral drugs that are delivered using lipid nanocapsules, such as antiretrovirals, have been able to successfully reduce the viral load in patients with HIV by producing successful clinical results. According to another study, lipid nanocapsules of cisplatin, which treats lung cancer, have been shown to significantly reduce the side effects of the drug, as well as to improve the drug's penetration into tumor cells. Based on the results of this study, it is evident that the use of lipid nanocapsules as a novel drug delivery system can greatly improve the efficiency and safety of drug delivery, as well as provide patients with a more pleasant treatment experience by significantly improving the efficiency and safety of drug delivery. Conclusion: As a new delivery system for drugs, lipid nanocapsules have the potential to improve their effectiveness and reduce their side effects. According to recent studies, this technology has the potential to be used to treat cancer, neurological disease, and infectious diseases. Eventually, this technology could be used in a wider range of applications as a consequence of further development and extensive clinical testing.