This study examined the effect of transcutaneous electrical nerve stimulation applied over acupoints (Acu-TENS) on forced expiratory volume, in patients with asthma, after exercise. Thirty subjects were randomly assigned to three groups. Group 1 received Acu-TENS over acupuncture points Lieque and Dingchuan for 45 min prior to a symptom-limited treadmill exercise test. Group 2 had Acu-TENS similarly applied prior to and throughout the exercise test. Group 3 mimicked Group 1 but without any electrical output from the device. Forced expiratory volume in one second (FEV(1)) and forced vital capacity (FVC) were recorded before, immediately after and at 20-min intervals post-exercise for 1h. Immediately after exercise, FEV(1) and FVC rose in Group 2 (p=0.015), but decreased in Group 1 and more so in Group 3. The differences became even more marked at 20, 40 and 60 min. Adjunctive Acu-TENS therapy appears to reduce decline of FEV(1) following exercise training in patients with asthma.