Half an hour. Go to the toilet after drinking orange juice for half an hour. The function of orange juice is to clear away heat and toxic materials, reduce fire, and eliminate phlegm and toxic materials. Oranges are cold, bitter and sweet. Clinically, it is often used to treat hepatitis B, hyperlipidemia, hypertension, diabetes, cold and fever, diarrhea, dysentery, eczema, throat discomfort and so on.