What is EBM?
Evidence based medicine is the integration of best research evidence with clinical expertise and patient values.
"EBM is the integration of clinical expertise, patient values, and the best evidence into the decision making process for patient care. Clinical expertise refers to the clinician's cumulated experience, education and clinical skills. The patient brings to the encounter his or her own personal and unique concerns, expectations, and values. The best evidence is usually found in clinically relevant research that has been conducted using sound methodology."  
EBM is "the conscientious, explicit and judicious use of current best evidence in making decisions about the care of the individual patient. It means integrating individual clinical expertise with the best available external clinical evidence from systematic research."
"Evidence-based medicine is the use of mathematical estimates of risk of benefit and harm, derived from high-quality research on population samples, to inform clinical decision making in the diagnosis, investigations or management of individual patients." 
Evidence based medicine is a set of principles and methods intended to ensure that to the greatest extent possible, medical decisions, guidelines, and other types of policies are based on and consistent with good evidence of effectiveness and benefit. 
Misunderstanding regarding EBM - 
EBM: A commentary on common critisims - 
What is EBM and how do we teach it?
Evidence-based medicine (EBM) is like safe sex: talked about a lot, preached (taught) a little and practiced infrequently. One problem is the lack of a common understanding of what the practice of EBM means. Some think it is doing systematic reviews; others think it is writing or implementing guidelines.
While such activities, if done appropriately, may support EBM they are not EBM. At least not according to the original conception of EBM as a means of directly informing day-to-day patient care with current research evidence (Straus et al., 2005). That involves asking and answering questions as we go about our daily clinical work: what might now be termed ‘workplace learning’. Given the disparate uses of the term EBM, we recently introduced the phrase ‘bedside EBM’ to try to recapture this original meaning (Glasziou & Haynes, 2005). The meaning of EBM is a holistic approach to patient care incompassing three key components; best research evidence with clinical expertise and patient values.