In many cases, the sonography of the endometrium requires an exact pre-therapeutical interpretation. Apart from a hysteroscopy, this can take place by means of an improved version of a contrast hysterosonography, i.e. the Gel-KHSG. The technique and examination results are described here. This simple examination method can--like hysteroscopy--precisely define or exclude anomalies of the endometrium, and, beyond that, it has the advantage of the sono-tomographic depiction of the uterine wall. Moreover, it can be taken assumed, that the vagino-sonomorphological diagnostics at the endometrium could--for instance, analogous to the colposcopy of the uterine portion--become part of a system of preventive diagnostics for the cavum uteri. However, such a system has not been set up to date.