Forty women with premenstrual tension received either placebo, 100, 200 or 400 mg danazol daily for 3 months in a pilot study arranged as a double-blind trial. Thirteen patients withdrew by the third month usually because they complained of no improvement. They had significantly higher pretrial symptom scores than those who continued. In patients treated with danazol, symptom scores for breast pain during the second and third months and for irritability, anxiety and lethargy during the third month were significantly (P less than 0.05) lower than scores in those given placebo. Most symptoms improved on placebo in the first month but by the third month only three remained improved. In contrast eight symptoms were improved on 200 mg danazol by the third month. By the end of the trial more than 75% of patients who were still taking danazol were essentially free of breast pain, lethargy, anxiety and increased appetite, but results for other common symptoms were no better than with placebo.