However, there are cases where the color may appear yellowish, sometimes referred to as âyellow spermâ or âyellow semenâ. The cause of yellow sperm is uncertain but it is believed that it can be caused by infection, or foods which are rich in sulfur such as garlic and onions.Another possible cause for yellow semen could be the natural thickening of semen; especially if you have not ejaculated for quite some time.he cause of yellow sperm is uncertain but it is believed that it can be caused by infection, or foods which are rich in sulfur such as garlic and onions.
Red dye or purple dye masks the lining of the colon and can interfere with getting accurate results. Here is a Top Five list of red and purple foods and drinks to avoid before your colonoscopy: Jell-OâAvoid strawberry, raspberry, cherry or black cherry and grape. PopsiclesâAvoid any red or purple in a variety pack. Try the natural frozen fruit bars made with real fruit juice.
Preparing for Your Colonoscopy. Learn what you need to do to prepare for your colonoscopy: 1  Three days before your colonoscopy, eat only low-fiber foods. 2  Also, stop taking any fiber supplements or anti-diarrheal medication. 3  Two days before, continue eating only low-fiber foods. 4  One day before, go on a clear-liquid diet.