Orange

It is possible for dogs to experience a reaction to oranges after ingesting them or encountering them as an environmental allergen.

While they aren't quite as bitter or acidic as lemons, oranges still contain enough citric acid to cause stomach upset in dogs if they ingest too many, regardless of whether they have an intolerance.

In fact, your pup may turn its nose up at oranges altogether! This goes for other citrus fruits as well since dogs aren't fans of strong citrus scents.