Bismuth Iodoform Paraffin Paste (BIPP) is one of the most commonly used packs after middle and external ear surgery. Only two retrospective case studies exist which found a 0.4% and 6% overall risk of BIPP allergy. The result of our prospective patch testing study identifies the true incidence of BIPP allergy to be 12% in those previously exposed and 1% in those not previously exposed. The component part responsible is iodoform not iodine. We recommend patch testing patients previously exposed to BIPP undergoing ear surgery, if postoperative BIPP packing is being considered. We recommend those patients allergic to BIPP should be tested with its constituent parts for future reference. It is important to determine whether there is allergy to iodine solution or not as this would preclude them from future iodine solution contrast studies and iodine solution skin prep before surgery. We do not recommend testing patients not previously known to be exposed to BIPP as the incidence of allergy is low and there exists a risk of sensitization.