Civil lawsuits brought for injuries to students are a source of growing concern for teachers, and especially for science teachers. This paper outlines some basic principles by which science teachers may protect themselves from lawsuits, before and during the time that students are engaged in experiments or lab work. Courts in this country have determined that educators have the following obligations to students: (1) adequate supervision; (2) proper instruction; and (3) maintenance of equipment. Accordingly, this monograph addresses each of these concerns. The teacher has the responsibility of thinking through each step of the experiment and analyzing the possibility of harm at each point, both from the process and from the equipment. Obvious potential hazards must be removed, since students cannot be subjected to unreasonable risk. In civil cases, teachers' actions are measured with reference to a hypothetical reasonable person under the same circumstances, or with reference to the doctrine of foreseeability. The best safeguard for today's science teachers is therefore comprehensive and explicit instruction before laboratory work. (TE)