Nanomaterials are getting rapidly developing practical applications, beside many others also in the clinical practice. Their beneficial attributes make the use of the nanostructures a large improvement in effective therapy as coating of implants, bone replacement materials, coating of active substances, nano-sized liposomes to achieve better pharmacologic qualities. Beside new beneficial chemical qualities originating from their size, due to the use of nanomaterials also adverse health effects may occur. Only in view of the possible effects on human health is the responsible use acceptable. The difference in qualities from other kinds of material can be explained by the nano-size. Investigations performed in the last decade have shown beside their local effect also systemic effects, like the rise of reactive oxygen species production, increase of platelet aggregation, which raises the cardiovascular risk. Due to the incomplete knowledge available now, it is not possible to assess the exact health risk; accordingly the application of nanomaterials in medical care has to be especially careful because of their possible partly unknown adverse health effects.