Healthy Diet 
A proper diet is key to your bunny's good health. Their digestive system and nutritional needs are very specialized, but once you know the basics it is easy to follow. The diet for adult rabbits should consist mostly of hay (unlimited amounts), with leafy greens next, followed by a limited amount of Timothy pellets and very limited treats such as fresh fruit or carrots. We strongly recommend the Oxbow Bunny Basics/T pellets as it is a high quality blend and doesn't contain unhealthy fillers like a lot of the cheaper pellets. It is also important to keep your bunny's diet consistent; any changes should be done very gradually. Bunnies should never be given nuts, seeds, 'human' treats or sugary things like yogurt drops sold in many pet stores as those are not good for their health or digestive systems.

Click on this link to a very informative article about diet from The House Rabbit Society: http://www.rabbit.org/faq/sections/diet.html