There are considerable benefits, both for patients and hospitals, if operations are done as day case procedures. Excision of a submandibular gland is a relatively common operation and it is usual practice for surgeons to be cautious, admit the patient for an overnight stay, and leave a drain in place. To assess the amount of postoperative bleeding into the wound (and hence potential risk to the airway) we have studied prospectively the amount of drainage that occurs. Sixty consecutive patients admitted for overnight postoperative monitoring after excision of a submandibular gland had a suction drain placed as part of the procedure. Drainage was measured by departmental staff at regular intervals during the following 24 h. Nearly all the patients drained 40 ml or less (mean 18 ml) and in all cases there was a clear decrease in the volumes drained over the first 6-8 h postoperatively. Drainage then became negligible. The plateau in drainage was evident regardless of the initial volume drained. Surgeons should be confident that drainage will cease after 6-8 h in most patients, and residual drainage is negligible.