This has been a gauranteed occurance for me, any time I trip on any psychedelic. Smoking weed on it is guaranteed to worsen it, and it always lasts for at least a day or two afterwards. It's not your diet. I eat nothing but whole grains, fruits and vegetables, specifically for constipation and it doesn't make a difference. It's like my intestines are squeezed shut, and they struggle to force it out of me, bit by bit, in small unusually dark balls. I should also add that my body sometimes reacts VERY badly to cannabis when tripping and sometimes just when my tolerance is low. It hasn't been entirely consistent(at least over the course of when it started to now) in *what* it does, but this past year, I've only had about 2 trips that didn't cause issues. The problems ranged from painful joint locking in my hands, wrists, arms(unable to open a box of cereal, and one time my arm was locked behind my head) and a few times in my knees, to swollen prostate leading to urine retention, and even extreme hair shed(Happened at least 4 different times, twice in one trip, both times just 2 to 3 minutes after finishing a bowl.) However, the thing that's always present are the intestinal issues you just described. I suspect I have some kind of autoimmune disorder, but doctor's haven't been able to find much.(It's easy to right me off as a hypochondriac, but these effects are too repeatable and physical.) The really bad effects seem to be entirely a reaction to smoking cannabis, for me. Although, I had about a 2 month period where it gave me no issues, I had a trip this last weekend which resulted in the acute urinary retention I mentioned, and caused the two large hair sheds in a row. I waited two days for the LSD to leave my system to smoke one last bowl of weed, and now(exactly one week after the trip, and 5 days after my last bowl) I still can't empty my bladder completely, and my large intestines feel like they're crammed full of rocks(still take a shit every day, with no problem). I know this question is about LSD, but I've been dealing with this and other unexplainable adverse reactions to things that should be physically safe for most people. I've only found a few posts online from people describing similar reactions, but no one with all them. I just wanted to put this out here, because I know these places are full of biased people who assume that because it causes most people no issues that those of us who do are either delusional or liars. I don't want people to think that I'm labeling either of these drugs as the cause, because my health just took a massive dip this last year out of nowhere. But, I want to emphasize that no one has the same genetic makeup, and the human body is an intricate system with plenty of opportunities to malfunction.
P.S.
I also wanted to add that I had tripped on high doses while smoking weed for a good year and a half with no issues before this. It started one day while I was tripping, directly after eating an apple. It felt like a sharp rock digging through my liver. I had my gallbladder removed, because it seemed at the time that that was the issue. Ever since then it's guaranteed to happen. Not eating anything before the trip helped with the severity of it, but it doesn't prevent it.
