In recent years, drug delivery systems (DDS) have been developed, along with anticancer agents for those systems based on the concept of achieving a better clinical response and tolerability. Several clinical trials have shown that these drugs have better clinical effects in the treatment of many cancers, leading to their expanded indications. Liposomal doxorubicin is one DDS agent used to treat AIDS-related Kaposi’s sarcoma and ovarian cancer in Japan. In addition to those two indications, the Food and Drug Administration (FDA) approved this drug for the treatment of multiple myeloma in 2007. Another DDS agent approved in Japan is nanoparticle albumin-bound paclitaxel, which has been used in the treatment of breast cancer. Most recently, this drug has been approved for the treatment of non-small cell lung cancer in the U.S.A. Although these DDS agents appear to be less toxic than conventional drugs, DDS-specific side effects such as various skin reactions, hypersensitivity reaction, and peripheral neuropathy sometimes occur. Therefore, medical staff must understand DDS anticancer agents fully, including characteristic side effects, to achieve the desired clinical outcomes.