A recent Appellate Court opinion in a premises liability case alleging back pain has the potential to be a pain in the neck for defense lawyers seeking to argue for possible alternative causes of plaintiff’s injuries in a personal injury cases in Illinois. In Campbell v. Autenreib, 109 N.E.3d 332 (2018), the Fifth District held that testimony about the potential alternative causes of plaintiff’s injuries elicited through cross-examination of the plaintiff’s treating physician was too speculative to be admitted in the absence of any defense expert testimony supporting the alternative causes. This opinion expands on the Illinois Supreme Court’s opinion in Voykin v. Estate of DeBoer, 192 Ill. 2d 49 (2000), which held that in most cases defendants must present expert testimony about the relevance of a prior injury or medical condition in a personal injury case.