Evidence-based pharmacy, both hospital and community pharmacists use the best available evidence when making decisions for patients. In evidence based pharmacy, pharmacist should take into account the patient's situation, the values and conditions when making decisions. Evidence is the drug for the pharmacist and pharmacists can contribute to the formation of evidence with notification of adverse effects. Increasing patient expectations, aging population, advances in medical technology have increased the importance of evidence based pharmacy today. In evidence based treatment, medical errors and health care expenditures is reduced, the scientific evidence is increased with pharmacist's contribution.