Citrus is the combined term used for a genus of flowering trees and shrubs in the rue family (Rutaceae). These plants produce edible citrus fruits, including oranges, lemons, grapefruits, and limes.

Most citrus fruits, like oranges, tangerines, grapefruits, and clementines, are eaten fresh after peeling the bitter rind. Citrus fruits are commonly juiced and used to complement soft drinks and alcoholic beverages. The more bitter fruits are used in jams and preserves with sugar to adjust the taste.

Allergies to citrus fruits are rare. Allergic reactions to raw citrus fruits are sometimes seen in people who have similar pollen allergies which is known as cross-reactivity.

People who are allergic to grasses, in particular, may experience allergy symptoms to citrus fruits. A 2013 study of 72 children and young adults with grass pollen allergies studied exposure to fresh lemon, orange, and clementine with a prick test. It found that 39 per cent of the participants who were allergic to pollen also had sensitivities to citrus.

Symptoms of citrus allergies include:

  Swelling of the face or lips
  Rash or hives
  Abdominal cramps
  Nausea or vomiting
  Diarrhea
  Anaphylaxis (rare)

Citrus fruit sensitivity or intolerance is where a person presents various digestive symptoms after the consumption of citrus-derived products. A less severe condition than an allergy, this condition can still be uncomfortable and embarrassing for the individual.

Symptoms of citrus intolerance or citrus sensitivity include:

  Bloating
  Diarrhea
  Tiredness
  Gas