KIE: Procedural and ethical aspects of phase I clinical trials of anti-cancer agents are examined to guide physicians in their role as advisors to patients enrolled in such trials. These phase I trials, designed to establish the toxicity and therapeutic potential of the drugs, are conducted in patients with extensive metastatic disease. The question is raised whether these patients are more vulnerable to constraints and inducements that impair a research subject's autonomy, and are therefore in need of additional protection in the consent process.