Several states, including Illinois, prohibit defense counsel from communicating with a plaintiff’s health care provider ex parte (i.e., outside of formal discovery). See, e.g., Petrillo v. Syntex Laboratories Inc., 148 Ill. App. 3d 581, 499 N.E.2d 952 (1st Dist. 1986). Petrillo held that such ex parte communications violated Illinois discovery rules and might lead treating doctors to improperly disclose patient confidential information to their patient’s adversary.