(S)-10-Hydroxycamptothecin is a naturally occurring alkaloid isolated from the Chinese tree *Camptotheca acuminata*. It is a pentacyclic quinoline derivative and a structural analog of the potent anticancer agent camptothecin. The key structural feature is the presence of a hydroxyl group at the C-10 position of the camptothecin core, which significantly influences its pharmacological properties. This compound is a potent topoisomerase I inhibitor. It functions by stabilizing the covalent complex between topoisomerase I and DNA, leading to the accumulation of DNA single-strand breaks during replication and ultimately triggering apoptosis in cancer cells. (S)-10-Hydroxycamptothecin itself has demonstrated significant antitumor activity in various preclinical models. More importantly, it serves as the direct precursor for the semi-synthesis of irinotecan and topotecan, two clinically important chemotherapeutic drugs widely used in the treatment of colorectal, ovarian, lung, and other cancers. Due to its poor water solubility, the clinical application of the parent compound is limited. However, its derivatives, particularly irinotecan (a water-soluble prodrug) and topotecan, have become cornerstone agents in oncology. Research continues to explore novel formulations and analogs of 10-hydroxycamptothecin to improve its bioavailability and therapeutic index.