"In the real world of dentistry, the professional maturity, the grit and the mettle of the dentist are tested in his or her reaction to the presentation of unexpected, emergency conditions". Can the dentist accept the responsibility for a patient whose state of health is unknown ? certainly not. Only thorough compilation of a accurate case history can the dentist know patients state of health and thus avoid interactions between drugs that could become serious. Luckily these occasions are rare, but the techniques of emergency treatment are essential to save human life.