Yes, there are natural alternatives to remove urine stains around the base of a toilet. One option is to use a mixture of vinegar and water. Simply combine equal parts of vinegar and water in a spray bottle, spray it onto the stained area, and let it sit for a few minutes. Then, scrub the stains away using a brush or sponge. Another natural option is to use a paste made from baking soda and water, which can be applied to the stains and scrubbed off after a few minutes.