Objectives: To determine the effect of the use of drainage tubes in relation to the inflammatory response and postoperative pain in extractions of impacted lower third molars. Material and methods: An experimental, randomized study on the response of edema and pain was conducted on 20 patients in relation to the use of drainage. The patients included had to have underwent extraction of their 2 impacted lower third molars, which had to be in a similar position. The same surgical procedure was used. A surgical wound was sutured in order to achieve healing at first attempt, and was considered the control side. In the contralateral side, a drainage tube was installed for 48 h in the surgical wound, this being the experimental side. To compare the edema of both sides, a standardized clinical photography and a numerical measurement were taken for each patient, preoperative and 48 h after the surgery. The pain was then assessed using the visual analog scale, 48 h and one week after the surgery. Results: According to this study, the use of a drainage tube decreases, with a statistically significant difference, the postoperative edema compared to the wounds sutured without drainage in the extraction of impacted lower third molars. On the other hand, there were no significant differences regarding the pain response when comparing both sides. Conclusions: The use of drainage after removal of impacted third molars reduces the edema, improving patient comfort in the postoperative period.