Is your drain starting to run rather slow? Or is it blocked all together? Well a very simple environmentally friendly way of dealing with blocked drains or plugholes is as follows.
Pack the drain or plug hole with as much baking soda (bicarbonate of soda) as possible. Boil up a pint of vinegar. VERY, VERY CAREFULLY pour the vinegar down the drain, keeping your face well out of the way. There will be a very violent reaction. Let it all sit there for 2 hours and then flush through.
Another way of dealing with a drain that is blocked is to flush the drain through with a garden hose that has a hard stream nozzle fitted. The force of the water will shift most obstacles.