There is evidence from a number of centres that some forms of locally advanced and aggressive cancers which are difficult to eradicate by standard means can be reduced by the use 01 “basal” chemotherapy to a degree which will allow more certain tumour eradication by subsequent radiotherapy and/or surgery. Clinicians have been divided as to whether there is an advantage in giving the chemotherapeutic agents directly into a regional artery of supply where this is feasible, as opposed to their systemic administration. This paper documents supportive evidence that some and possibly many chemotherapeutic agents are more effective if given regionally into an artery of supply. There is a higher incidence of local side‐effects in the region infused, including loss of hair, inflammatory changes, and ulceration of the skin or mucosa of the region infused. After intraarterial infusion of tagged bleomycin (indium‐Ill bleomycin) into a limb, the radioactive isotope remained more concentrated in the limb infused than in the opposite limb for at least 24 hours. Systemic side‐effects, including bone‐marrow depression, are less frequent and less severe in patients given chemotherapeutic agents by intraarterial infusion than if the same doses of agents are given intravenously. There is now sufficient evidence of the value of basal chemotherapy used in this way to make it mandatory that medical oncologists and surgeons, working together, should plan controlled studies to determine the most appropriate applications of this technique of management.