Today, the use of biological materials, both in the form of drug supplements and in the form of enriched foods, has been considered. These substances have shown various properties such as anti-inflammatory, anticancer, antidiabetic, immune system booster, and antimicrobial. Although these compounds originate from natural sources, they have little stability against environmental conditions. Encapsulation is an effective method that can increase the chemical and biological stability of biological compounds and also protect them from inevitable reactions. Compared with microcapsules, nanocapsules have a higher surface-to-volume ratio and are of great interest for in vivo and ex vivo biological applications. Polymeric nanocapsules can be prepared from natural or synthetic polymers. Encapsulated bioactive compounds should be released at the right time and place. Several release mechanisms have been proposed for trapped bioactive compounds, including simple diffusion, swelling, and decomposition with diffusion. Release under the influence of environmental conditions such as solvent, temperature, pressure, molecular interactions, changes in pore size, and network disintegration.