Saute the sliced mushrooms in the olive oil for about five minutes, or until they start to give off their moisture. Mix the tangerine juice (I'm sure you could use orange juice), the sherry, the brown sugar, and the horseradish together and pour over the mushrooms. Cook over medium heat for about ten more minutes until the sauce has reduced by one-half and has glazed the mushrooms.
I actually started feeling much better after I ate this concoction and think I will keep the recipe to use as a side dish with chicken or over rice for a light supper.