Nanoparticles (NPs) have various applications in biomedicine and drug delivery carriers and also are widely used in cosmetics. However, the preparation of biocompatible and non-toxic nanomaterials is a very important issue as most of the starting materials are synthesized using toxic chemical reagents. This review introduces the preparation of biocompatible NPs in a range of their concentrations using phytochemicals for biomedicine and biotechnology. Phytochemicals are natural products that are extracted from plants, vegetables, and fruits. Phytochemicals serve as reducing agents and stabilizers during NP synthesis to convert metal ions to metal NPs in water. Possible applications of such nanomaterials in biomedical sciences are also described in this review.