Cedar Fever

 Yes, it's possible to experience an upset stomach or intestinal discomfort from cedar fever (an allergy to mountain cedar pollen) because allergies can sometimes manifest gastrointestinal symptoms, including nausea, diarrhea, and abdominal cramps, due to the histamine release triggered by the immune response; essentially, your body's reaction to the pollen can affect your digestive system as well. 

When your body reacts to allergens like cedar pollen, it releases histamine, which can cause muscle contractions in the digestive tract, leading to stomach upset.

While typical cedar fever symptoms include runny nose, itchy eyes, sneezing, and a sore throat, some people may also experience mild stomach discomfort, nausea, or diarrhea.