Drugs used in various combinations, have had considerable influence in cancer therapy but, unless improved products appear, they are not likely, alone to be capable of controlling the disease. Immunological methods have, so far, made little impact on cancer therapy although tumour specific antigens provide a difference between normal and neoplastic cells which should be taken advantage of. Encouragement of active immunity in cancer suffers from the disadvantage of being imposed upon an immunologically depressed state, normally encountered in cancer and increased by the use of drugs which are frequently immunosuppressive in themselves. We are using passive immunity, for example animals are immunised against human tumours and the sera absorbed to remove anti-human and to leave anti-tumour antibodies. These we use to attach drugs to “home” to the tumour site. Various claims have been made for such an effect, but no therapeutic agent has emerged. Following work in mouse models, such drugged antibodies now exist and will be discussed elsewhere at this meeting. In the meantime we also have a synergism between drugs and antibodies which will be illustrated by mouse data. These systems are being tested clinically with encouraging results.