Foods to avoid feeding your rabbit:
Beets (sugary), Breakfast cereals, Chocolate (NEVER give this to any pet - it is poisonous to most), Corn (rabbits can't digest the hulls of the corn kernels), Diatomaceous Earth - this is made from finely ground shells, and even the highest quality can have edges which act like razor blades against the thin lining of a rabbits stomach lining. Do not use for food or litter,Fresh peas, Grains, Green beans (can cause gas),
Iceberg lettuce (and any light green lettuce leaves - they are high in water content but low in nutrients and may cause diahrrea) - can be gven in small amounts or when you have no other greens to offer, but watch the output for soft stools, Legumes, Nuts, Onions, Pelleted food with seeds mixed in (it's a treat to the bunnies but the seeds cause stomach problems), Potatoes (white or red), Seeds of any kind, Starches of any kind,
Sugar, in any form (small quantities of treats are allowed, but no more than a tablespoon of fruit or raisins or anything containing any types of sugar)
Foods that are toxic to rabbits:
Note: do not allow your rabbit to eat dried leaves from any trees - too many types are very toxic and some can cause cyanide poisoning (this includes specifically apple tree leaves, oak leaves, maple leaves, etc). If you allow your rabbit an outdoor run, please clear the area of leaves as the rabbit may find them very tasty, but they are very dangerous!!
Foods that contain compounds that destroy nutrients:
Sweet potato, Cassava, Bamboo shoots, Maize, Lima beans, Millet, Bracken fern, Tea leaves, Coffee plants.
Rhubarb leaves, Raw lima, kidney or soy beans, Onions, Citrus peels.
Oxalates (causes pain and swelling of mouth and throat, swollen tissue can restrict breathing or cause suffocation.)
Begonia, Caladium, Calla lily, Diffenbachia, Dumbcane, Jack in the pulpit, Philodendron, Schefflera.
Minor Toxicities (causes vomiting, diarrhea, nausea)
Aloe vera, Amaryllis, Bird of paradise, Birch, Boxwood Cedar, Chrysanthemum, Daffodil, Daisy, Eucalyptus, Galiola, Hydrangea, Haycinth, Iris, Juniper, Redwood tree, Rananculus, Sweet pea, Sweet william, Violas.
Extremely Toxic (one leaf can kill)
Angels Trumpet, Azalea, Black Acacia and Locast, Bleeding Heart, Carmellia, Carnation, Carolinia Jasmine, Castor Beans, Christmas Beans, China Berry, Clementis, Coffee Tree Plant, Cyclamen, Daphne, Delphinium, Easter Lily, Elderberry, Flax, Four-o-clocks, Geranium, Heavenly Bamboo, Hemlock, Holly Berries, Ivy, Jerusalem cherry, Lantana, Larkspur, Licorice plant, Lily of the valley, Lobelia, Milkvetch, Monkshood, Morning glory, Mountain laurel, Narcissus, Nightshade Loeander, Pea family, Pig weed, Potato plant, Pivet, Rhododendron, String of pearls, Thorn apple, Toyon, Vinca, Wintergreen, Wisteria, Tew. From: http://board.smallanimalchannel.com/Topic9319.aspx
Bamboo shoots when raw have cyanide. Cyanide is highly toxic and results in rapid breathing, pale extremities, coma, and possibly death. The toxins can depend from plant to plant but I would not risk it.
The ones sold for human consumption need to be cooked/treated to release the toxins.
It is not listed as a safe food for bunnies.
Hope this helps. Did extensive research and I found the best articles/websites that would hopefully help.