The need to find a safe and highly effective cure for neoplastic disease remains a major challenge for modern pharmacology. This paper reviews the available literature on Ukrain (NSC631570), a novel semisynthetic drug obtained from Chelidonium majus L. alkaloids. Ukrain has been demonstrated to possess antineoplastic and immunomodulatory properties. Inhibition of the growth of cancer cells lines in vitro, tumor mass reductions in vivo, and partial and complete remissions in oncological patients, occur as a result of Ukrain application. The drug may interfere directly with the matabolism of cancer cells and it also improves the functioning of the host immune system. Diminished synthesis of DNA, RNA and proteins, the inhibition of cellular oxygen consumption, and the induction of programmed cell death in malignant cells have been described following Ukrain administration. The drug can also modify the immunological response via an increase in the number of total T-cells and a normalization of the T-helper/T-suppressor lymphocyte ratio. Ukrain therapy produces neither toxic consequences nor allergic reactions towards the drug. Several case reports and clinical trial data indicate that Ukrain may ameliorate effectively the progress of neoplastic disease and/or induce a total cure.