Yes, you can be allergic to green beans, but it is very rare. Green bean allergy is a type of legume allergy that is caused by a protein in green beans that can trigger an allergic response. Some symptoms of green bean allergy are hives, itching, swelling, wheezing, coughing, sneezing, runny nose, nausea, vomiting, diarrhea, abdominal pain, or anaphylaxis (a life-threatening reaction that affects breathing and blood pressure). If you suspect you have a green bean allergy, you should avoid eating them and consult a doctor for diagnosis and treatment.