Objectives: 1. To estimate IgE and histamine levels in patients with drug allergy and with past history of drug allergy. 2. Compare these levels with that of normal individuals 3. Assess the association of demographic factors, nature of drugs and clinical presentation with IgE and histamine levels. Methodology: 113 potential participants were totally interviewed. 66 selected based on selection criteria. 22 had current allergy (CA), 22 past history of allergy (PA) and 22 without any allergy (NA). Study was initiated after getting IHEC approval and informed consent from each participant. Estimation of serum IgE and histamine was done using ELISA kits. Demographic details, details of drugs and clinical presentation were recorded. Time interval between onset of allergy and estimation of IgE and histamine was recorded for patients with PA. Results were analyzed using ANOVA and student t test. p<0.05 was considered significant. Results: IgE and histamine levels were significantly higher in CA compared to NA and PA subjects.