:: Bleu Cheese - the mould in it is toxic to rats
:: Carbonated Beverages - rats cannot burp, so the gas can cause severe discomfort.
:: Green Bananas - inhibits starch-digesting enzymes
:: Green Potato Skin and Eyes - contain solanine, a toxin.
:: Licorice - suspected to cause neurological poisoning in a rat.
:: Orange Juice - forbidden for male rats only, d-limonene in the skin oil, which gets into the orange juice during squeezing, can cause kidney damage and kidney cancer due to a protein that only male rats have in their kidneys. Pieces of the orange fruit are okay if you wash the orange-skin oil off of it after peeling it.
:: Raw Artichokes - inhibits protein digestion.
:: Raw Bulk Tofu or Meat- can contain bacteria, packaged raw tofu is safe.
:: Raw Dry Beans or Peanuts - contains antinutrients that destroy vitamin A and enzymes needed to digest protein and starches and causes red blood cells to clump.
:: Raw Red Cabbage and Brussel Sprouts - contains antinutrient that destroys thiamin.
:: Raw Sweet Potato - contains compounds that form cyanide in the stomach.
:: Rhubarb - contains high levels of oxalates.
:: Sticky foods such as Peanut Butter, some Candy, and Dried Fruits - poses a choking hazard. Peanut butter can be "cut" with jam or honey to make it more liquid, and reduce the possibility of choking.
:: Wild Insects - can carry internal parasites and diseases.

:: Dried Corn - can contain high levels of fungal contaminates which has been shown to cause liver cancer in rats.
:: Mashed Potatos - Choking hazard due to the pasty texture.
:: Avocado Pear - Be very careful when feeding avo to rats - avoid the area by the seed/stone and the dark green bits by the skin.