<p>The invention relates to a sterilisation device comprising a plug (50) which is capable of occluding a fallopian tube, the plug having an external thread (55) thereon wherein the thread has a root length in the range 0.8 to 1.5 mm and a pitch in the range 1.55 to 2.0 mm so that, upon rotational insertion of the plug into a fallopian tube, the plug grips the walls of the fallopian tube and resists removal from the fallopian tube. The device may form part of a sterilisation assembly further including a driver (105) configured to co-operate with the head (65) of the plug facilitating the transfer of torque from the driver to the sterilisation device. Also described is a method of female sterilisation comprising the steps of introducing the device into a uterine cavity and screwing the device into a fallopian tube. This may be executed using the assembly of the invention, or other methods.</p>
