Injection of substances for cosmetic reasons is the second most frequently performed invasive procedure worldwide. The incidence of complications is relatively low; however, the possibility of neurologic complication should be taken in account as they might be serious. Vascular complications include the occlusion of the ophthalmic artery and brain ischemic stroke, both caused after intravascular migration of the injected material. Immunological events are more difficult to characterize but may be a rare consequence of local or systemic inflammation induced by the presence of foreign substances, which trigger a cascade of persistent tissue damage. An early identification of such complications is important to start a prompt treatment and to prevent further sequelae.