Oranges are sweet and sour in nature. Oranges promote the digestion and benefit the spleen and liver. Oranges are therefore suitable for indigestion and poor appetite. Tangerines, clementines, satsuamas etc are beneficial for clearing phlegm from the chest or windpipes. Oranges though are damp and will not help phlegm or even create more phlegm and dampness. Oranges are good for preventing colds as they have a lot of vitamin C, but once a cold has taken hold they should be avoided, instead eat tangerines etc If you have skin disease or overactive immune system syndrome caused by too much heat and damp then oranges should be avoided. Oranges will also slow down blood circulation which maybe good for insominia or night sweats or palpitations, however high cholesterol or high blood pressure or poor circulation will be made worse.