Dogs can eat mandarin oranges in moderation. Mandarins, like other types of oranges, are non-toxic to dogs and can offer some vitamins such as vitamin C, but because dogs naturally produce vitamin C in their livers, they do not require supplementation from fruits. Mandarins have a high sugar content and acidity, so they should be given in small amounts to avoid digestive upset, and the peel must be removed as it can be toxic and cause gastrointestinal problems. Dogs with diabetes or sensitive stomachs should avoid mandarins due to their sugar and acid content. Overall, a few peeled, seedless mandarin segments provided as an occasional treat are safe for most dogs.