Nanomaterials are now widely used in various industries such as automotive, biomedical, cosmetics, defense, energy, and electronics, due to their unique properties. However, this ubiquitous presence of nanomaterials in the environment is inducing possible major issues of toxicity for humans. Indeed, nanomaterials can elicit toxicity in human cells. Here, we review nanomaterial exposure to humans, with focus on impact on human cells and animal models. We discuss mainly nanomaterials made of silver, gold, silica, quantum dots, iron oxides, zinc oxide, and titanium dioxide. There is evidence that nanomaterials accumulate in the heart, liver, spleen, kidney, and brain by including ingestion, dermal penetration, inhalation, and intravenous.