I got leather gloves and a pan and went out to harvest yaupon for tea. In the past I tried to follow preparation instructions (crushing, pounding, toasting) that were so involved that the tea didn't seem worthwhile. Today I stripped off the leaves and boiled them immediately. The fragrance in the kitchen is somewhat like cooking apple pie. The taste of the tea is so-so. Maybe I will get use to it. There is a slight caffeine buzz. Leaves were from a male plant. Leaves from a female plant are supposed to taste better, but at this time of year the females are covered with berries. My motive is to control side effects of necessary medication.
But since you asked, uncontrollable flatulence and diarrhea. This is a consequence of taking diltiazem for control of heart arrhythmia. Of course, I think that anything can be controlled if I put enough effort into it. Diltiazem relaxes smooth muscles, including those of the intestinal tract. Want to know what happens if one takes diltiazem? Just imagine what happens if peristalsis stops.
"Joel Waterfield. I'm sure June Faye (White) Cason knows how to make yaupon tea. Her mother Hettie (Waterfield) White made it and she and her husband Fred, daughter, Melva, Sons Alston, Rondel and Marvin drank it all their young life. I was told that some people even allowed it to ferment. I don't know how people drank the God awful stuff, there isn't enough sugar in North Carolina to sweeten a cup of Yaupon (Holly) tea. It would turn your teeth dark brown and draw in your mouth like a persimmon. Hettie and her husband Fred drank it all the time."
I enjoyed that, but properly brewed, the taste of yaupon is better than China tea.
The narration is humorous but does describe the laborious way of curing yaupon with heated stones.
"... the man in the black cap at the door is the Doctor J.J. Davis, at whose house I was boarding. He is buying a peck of tea for a quarter for my special delection. We had some that night at supper: I tried it straight. I tried it with milk and I tried it with enough sugar to make shoal water in the middle of my cup, but one of the boys looked at my cup so wistfully that I could not resist the dumb appeal and I let him finish it up. The doctor said it was all right, but on most other occasions I found him to be a truthful man."
Both sites allege that yaupon tea can reduce the symptoms of IBS, which is important if true because many have it. Also, no site on the internet mentions the faults of yaupon: cost and distaste. Commercially available yaupon tea costs from 5 to 20 times more than than yerba mate and green tea to which it is comparable. A home gardener in zones 7 - 9 can grow their own at no cost, my circumstance by accident. I've no idea how yaupon got here. It's rather weedy. As for distaste, a medicinal use of yaupon may require a much stronger and bitter brew than can be gotten from tea bags. Persons with a medical condition -- all of us eventually -- will happily put up with distasteful things to reduce symptoms. I have gotten around the bitterness of ultra strong brews by putting yaupon powder in capsules.
Historically in brewing yaupon tea, twigs were included with the leaves. What does this do to the tea? I tried brewing a cup of just cut up twigs. The resulting tea had a darker color than I expected but the flavor was unpleasant. I think yaupon tea is better without twigs.