Antiemetic therapy is provided to patients with cancer to prevent chemotherapy- induced nausea and vomiting (CINV), based on the emetic risk of anticancer agents. However, breakthrough CINV can occur despite appropriate antiemetic prophylaxis. It is preferable to administer the rescue dose of antiemetics in breakthrough CINV that occur at home, in a form that is immediately effective and that can be easily self- administered by the patient. In the present study, we examined and compared the blood pharmacokinetics of subcutaneous (SC) injection, a preferred route of self-injection, and intradermal (ID) injection, a less invasive route, with an aim of developing simple self- injectable rescue antiemetics. A single administration of four kinds of antiemetics via SC and ID routes in rats resulted in lowerTmaxvalues compared with previously reported oral administration, indicating that the administration of antiemetics via ID and SC routes may be effective in providing faster antiemetic effects and to alleviate patient symptoms.