The sensitivity of 66 gonococcus strains isolated from 35 men and 31 women suffering purulent secretion from the urethra was tested in vitro by determination of the inhibition zone to 3 antibiotics and to pure copper. Inhibition of gonococcus growth by copper were also studied in vivo in 15 women with positive cultures following the insertion of an IUD with pure copper. Observations following IUD insertion were very promising and gave completely negative results of the culture and the direct specimen in all but 1 case in which the disease had been localized in the cervical mucus. (author's)