Purpose: The third molar extraction is one of the mostly performed procedures in the department of oral and maxillofacial surgery. In most of dental clinic or hospital, the third molar extraction used to be frequently performed in an office-based surgery, and most patients did not have specific medical history with young ages. Medical history taking are dependent on the only way by asking to the patients about their individual conditions. Therefore, as the specialists of the oral and maxillofacial surgery in the field of dentistry, we suggest a new policy that the preoperative lab must be performed routinely before extraction of the third molar. Methods: This study is based on 1,096 patients who have been managed with third molar extractions, from March 2008 to September 2011 by a single surgeon. The preoperative lab, including complete blood count, coagulation panel, chemistry and serology, was performed before any surgical procedures. The results were informed to the patients regardless of their abnormalities, and any abnormalities related to the surgical procedures, such as platelet count and coagulation factors, were checked and corrected safely. Results: Through the preoperative blood test, systemic diseases that the patients had not recognized before, such as anemia, leukopenia, fatty liver and chronic renal disease, were identified. Patients with acute or chronic leukemia, Hepatitis B, and HIV positive, were also detected as a small number. Also, the possibilities of the cross-infection between dentists and patients or between patients and patients, and any other emergency situations can be prevented; as well as the public health condition can be improved, too. The patients were satisfied with low cost preventive blood test and high quality of medical services. Conclusion: Therefore, routine medical lab testing, including history taking are needed before an office-based minor surgery, such as third molar extractions, and these results were suggested as a new policy in the field of dentistry.