alpha 1-Blocking agents (alphuzosine and terazosine) have been tested to determine their effectiveness over a placebo in the treatment of premature ejaculation. A total of 91 patients, all of whom were resistant to psychological therapy, were submitted to a double-blind controlled cross-over trial. Side effects were recorded as well. Alphuzosine and terazosine proved effective in approximately 50% of the cases and were, thus, significantly more active than the placebo; moreover no significant difference was found between them in terms of side effects. It is concluded that alpha 1 blockers are reasonably safe active drugs, effective in the treatment of premature ejaculation which does not respond to the psychological approach.