Adjuvant Vitamin D With Corticosteroids in Active Crohn's Disease

Inclusion Criteria: 1. Active Crohn's Disease Activity (CDAI) Score \>200 to 450; 2. Diagnosis of IBD and distribution of disease previously confirmed 3. The participant able to give informed consent form; 4. Stable doses of the following concurrent IBD medications prior to inclusion: * 5-aminosalicylates (≥4 weeks) * Thiopurines (≥8 weeks) * No corticosteroids (within 4 weeks) * No biological agents (within 8 weeks). Exclusion Criteria: 1. Unable to give informed written consent; 2. Co-existence of any other chronic inflammatory conditions 3. Failure to meet concurrent IBD medication criteria; 4. Hypercalcaemia (Corrected serum calcium \> 2.66 mmol/L) or history of vitamin D hypersensitivity; 5. Diagnosis of any of the flowing: active tuberculosis, sarcoidosis, hyperparathyroidism, pseudohyperparathyroidism, nephrolithiasis, silicosis, liver failure, renal failure or malignancy, active TB, sarcoidosis or lymphoma or other granulomatous disease; 6. Known intolerance or contraindication to vitamin D or trial medication (i.e. corticosteroids / infliximab); 7. Biochemical disturbance at enrolment: serum corrected calcium \> 2.66 mmol/L) or serum creatinine \>250 micromol/L; 8. Pregnancy or breast-feeding.