Classic therapies are usually ineffective in the treatment of patients with very poor sperm density. The aim of this study was to determine the effect of acupuncture on these males. Semen samples of 20 patients with a history of azoospermia were examined by light microscope (LM) and scanning electron microscope (SEM), with which a microsearch for spermatozoa was carried out. These examinations were performed before and 1 month after acupuncture treatment and revealed that the study group originally contained three severely oligoteratoasthenozoospermic (OTA), two pseudoazoospermic and 15 azoospermic patients. The control group was comprised of 20 untreated males who underwent two semen examinations within a period of 2-4 months and had initial andrological profiles similar to those of the experimental group. No changes in any of the parameters examined were observed in the control group. There was a marked but not significant improvement in the sperm counts of severely OTA males following acupuncture treatment (average = 0.7 +/- 1.1 x 10(6) spermatozoa per ejaculate before treatment vs. 4.3 +/- 3.2 x 10(6) spermatozoa per ejaculate after treatment). A definite increase in sperm count was detected in the ejaculates of 10 (67%) of the 15 azoospermic patients. Seven of these males exhibited post-treatment spermatozoa that were detected even by LM. The sperm production of these seven males increased significantly, from 0 to an average of 1.5 +/- 2.4 x 10(6) spermatozoa per ejaculate (Z = -2.8, P < or = 0.01). Males with genital tract inflammation exhibited the most remarkable improvement in sperm density (on average from 0.3 +/- 0.6 x 10(6) spermatozoa per ejaculate to 3.3 +/- 3.2 x 10(6) spermatozoa per ejaculate; Z = -2.4, P < or = 0.02). Two pregnancies were achieved by the IVF-ICSI procedure. It is concluded that acupuncture may be a useful, nontraumatic treatment for males with very poor sperm density, especially those with a history of genital tract inflammation.