White Vinegar and either a lemon or lime works great for cleaning a slow drain. I have found that sometimes it can work better for for your bathroom drain than Drano and it's safer to use around your pets and children. Pour a couple of cups of white vinegar down your drain and then squeeze two lemons or limes down your drain. The mixture of the two will eat away all the slime from your drain. Drano will help, but it won't clean the drain spotless, not like the vinegar and lemon. No more running to the store when your in a pinch with your drain.