Irinotecan, sold under the brand name Camptosar among others, is a medication used to treat colon cancer, and small cell lung cancer. For colon cancer it is used either alone or with fluorouracil. For small cell lung cancer it is used with cisplatin. It is given intravenously. Irinotecan was approved for medical use in the United States in 1996. It is on the World Health Organization's List of Essential Medicines. It is made from the natural compound camptothecin which is found in the Chinese ornamental tree Camptotheca acuminata.