Your orange is red inside because it’s either a blood orange or a Cara Cara navel, two varieties that naturally produce red or pink flesh. This is completely normal and safe to eat. The color comes from plant pigments that regular oranges don’t produce, and in most cases, the red flesh actually signals higher antioxidant content than a standard orange.
That said, there’s a small chance the discoloration isn’t natural pigment but a sign of internal rot. Here’s how to tell the difference and what’s actually happening inside your fruit.
Blood Oranges vs. Cara Cara Navels
Two distinct types of orange have red interiors, and they get their color from completely different pigments.
Blood oranges have deep red to maroon flesh, sometimes with streaks or patches rather than uniform color. The most common varieties are Moro (the darkest), Tarocco, and Sanguinello. Their color comes from anthocyanins, the same family of pigments found in blueberries, red cabbage, and red wine. A genetic mutation, specifically a small piece of DNA that inserted itself near a color-controlling gene, allows blood oranges to produce these pigments when exposed to cold temperatures. The first known description of a blood orange dates to 1646 in Italy, where a Jesuit scholar wrote about a purple-fleshed orange that “tasted strangely like a grape.”
Cara Cara navels look more pinkish-red, similar to the inside of a ruby red grapefruit. Their color comes from lycopene, the same pigment that makes tomatoes red. Unlike blood oranges, Cara Caras don’t need cold weather to develop their color. If you bought a navel orange and were surprised by pink or salmon-colored flesh, it’s almost certainly a Cara Cara.
Why Some Blood Oranges Are Redder Than Others
If you’ve bought blood oranges before and noticed the color varies wildly from fruit to fruit, that’s not a quality issue. It’s a temperature issue. Blood oranges develop their red pigment best at nighttime temperatures between 46°F and 59°F (8°C to 15°C), and they need roughly 15 to 30 consecutive days in that range to reach their deepest color. This is why Sicilian blood oranges, grown in a Mediterranean climate with long hot summers followed by cool winter nights, tend to be the most intensely pigmented.
Blood oranges grown in Florida, by contrast, often disappoint. Florida’s winters are mild with only occasional cold snaps, which isn’t enough sustained cool weather to trigger strong pigment production. California-grown blood oranges fall somewhere in between, with their season running from November through May. Texas blood oranges are in season December through March.
If your blood orange looks more orange than red inside, it was likely harvested from a warmer growing region or picked before enough cold nights accumulated.
How Red Oranges Taste Different
Blood oranges have a flavor profile distinct from regular oranges. They carry a berry-like, slightly tart quality that standard navels and Valencias lack. Research comparing pigmented and non-pigmented oranges found that deeply colored blood oranges contain significantly higher levels of fruity ester compounds, sometimes double the concentration found in lighter-colored fruit. These esters contribute floral and berry notes that make blood orange juice taste noticeably different from regular orange juice.
Cara Caras are sweeter and less acidic than standard navels, with a mild, almost cherry-like undertone. They lack the berry complexity of blood oranges but are generally considered easier to enjoy straight off the cutting board.
Nutritional Differences Worth Knowing
Red-fleshed oranges aren’t just visually interesting. Blood oranges contain higher levels of vitamin C than standard “blond” oranges, along with anthocyanins that function as antioxidants. The Moro variety in particular is rich in both anthocyanins and hydroxycinnamic acids, another class of antioxidant compounds. Cara Caras contribute lycopene, which blond oranges produce in negligible amounts.
None of this means you need to switch from regular oranges. All oranges are excellent sources of vitamin C. But if you’re choosing between varieties at the store, the red ones do carry a broader range of beneficial compounds.
When Red Means Something Is Wrong
In rare cases, unusual discoloration inside an orange signals rot rather than natural pigment. Alternaria rot, a common citrus fungal disease, causes dark brown to black firm blotches that typically start at the bottom (navel end) of the fruit and extend into the core. The key differences are easy to spot:
- Natural pigment: Uniform or attractively streaked red/pink color throughout the flesh segments. Fruit smells fresh and citrusy. Texture is firm and juicy.
- Fungal rot: Dark brown or black discoloration, often concentrated near the navel or core. Flesh may feel soft or mushy in spots. Off-putting or fermented smell.
If the red color is evenly distributed through the segments and the fruit smells and feels normal, you’re looking at a naturally pigmented variety. Alternaria rot also tends to develop during storage, so an orange that looked fine when you bought it but develops dark internal patches after sitting on the counter for weeks is more suspicious than one that’s uniformly pink or red when you first cut it open.
How to Find Red Oranges on Purpose
If you enjoyed the surprise, you can seek these out intentionally. Blood oranges are typically available in grocery stores from December through April in the Northern Hemisphere, with peak color intensity in February and March. They’re often labeled by variety name (Moro, Tarocco, or Sanguinello) or simply as “blood oranges.” Cara Cara navels are easier to find and have a longer season, usually appearing from November through May. They’re almost always labeled as “Cara Cara” at the store.
Look for blood oranges with a slight blush of red or burgundy on the rind, though this isn’t always a reliable indicator of internal color. The only guaranteed way to know how red they are inside is to cut one open.