A method of modifying or adjusting a component part of a colostomy device 10 includes the step of making an incision in the component part using a laser. The incision removes a portion of the colostomy appliance to adjust the device to a desired size. The component part is a peripheral wall 13 around the opening 12 for receiving a stoma in a colostomy device and the adjustment is to circumferentially cut 31, 32, 33, 34 the wall 13 to a desired size.