A basic rule of Anglo-American law is that an individual has no duty to another person unless there is a legally recognized relationship with that person. Physicians have many legal relationships, all of which have accompanying duties that might form the basis of a lawsuit. In some cases, the defendant will deny that there was a legally recognized relationship with the plaintiff. If the plaintiff’s claim is based on medical malpractice, the plaintiff must allege facts to support the existence of a physician–patient relationship. If the patient does not make the factual allegations necessary for the court to find a physician–patient relationship, the plaintiff’s lawsuit will be dismissed. This often happens if a patient sues several physicians and includes one who did not treat the patient and had no legal relationships with the physicians who did treat the patient.