A new technique is described for the treatment of menorrhagia by heating the whole of the endometrial cavity of the uterus. A capacitively coupled probe at 27.12 MHz is inserted into the uterine cavity, which causes the basilis layer to be raised to approximately 50-55 degrees C whilst the rest of the pelvic contents remain at approximately normal (body) temperature. A major advantage of the method is that no special hysteroscopic skills are required, unlike the two other techniques currently used for endometrial ablation: the Nd-Yag laser or the hysteroresectoscopic loop. Also no toxic flushing/distension fluids are necessary, as are required for all hysteroscopic surgery. The method, however, does require the application of a large amount of RF power to the probe and so care must be taken to position the probe correctly in order to prevent any serious complications. Of 32 patients given a single treatment at a power level of 550 W for 20 min, the 'success rate' was 84% with 31% becoming amenhorrhoiec and 53% showing significant reduction in menstrual bleeding. However, retreatment is possible and by this means, combined with improved treatment techniques, an even higher success rate could be achieved. In two of the earlier patients treated at 550 W a fistula was produced at the anterior vaginal wall which had to be surgically repaired. The probe was subsequently modified, since when this problem has not recurred. This new treatment approach offers an alternative to hysterectomy in the treatment of menorrhagia and may offer a number of significant advantages over methods currently used for endometrial ablation.