Within highly evolved national drug regulatory authorities much effort is directed to establishing the efficacy and safety of new drug entities through pharmaceutical, biological, and clinical assessment and through subsequent surveillance of their performance in routine use after marketing. Premarketing assessment is dependent upon detailed multidisciplinary technical review, and postmarketing surveillance requires a highly developed health care infrastructure. Only in exceptional circumstances should a small regulatory authority contemplate allocation of scarce resources to these ends. Reliance must be placed primarily on information notified by other countries through the network of national information officers established by WHO.