This study investigates the potential of combining allopurinol and thiopurines to improve symptoms of inflammatory bowel disease (IBD) and predicts complications using various variables. Thiopurines and allopurinol are both utilized in IBD treatment. Regression models were employed to predict white blood cell and metabolite levels. The study involved approximately 27 groups of subjects, including 20 voluntarily treated individuals and seven mistakenly diagnosed with gout and inadvertently treated. Among 16 patients initially on steroids, seven no longer required them, and 13 out of 20 showed significant clinical improvement. However, five infections were reported, including two cases each of shingles, PCP, and EBV. Significant relationships were found between thiopurine and allopurinol doses, body mass index (BMI), age, and metabolite levels. BMI increased with age and dose, while white blood cell counts decreased. Patients without infections had an average of 850 lymphocytes per mm3, despite only five events occurring. Allopurinol served as an adjunct treatment for 48% of shunt patients, yet the incidence of opportunistic infections remained notable. This study underscores the importance of vigilance, particularly in monitoring lymphocyte counts, to detect and prevent opportunistic infections in IBD patients undergoing combined therapy with allopurinol and thiopurines.