I'd avoid it if you don't have a strong sense of self and a decent understanding of how you work. If you have any misconceptions there's a chance they'll get blown out of proportion.
Example: a clueless introvert with a touch of social anxiety walks into a crowded room, gets overwhelmed by the massive stimulus of so many people and conversations, notices someone looking at them, gets slightly embarrassed and makes a quick exit with a blank mind followed by spending several hours later that day wondering why they acted like that.
Same person on acid walks into the room, isn't entirely overwhelmed, 'sees' things like a couple fighting across the room, knows that he cheated on her from the way he glances at some chick walking by; sees someone else looking unhappy and knows they'd rather be somewhere else entirely because they don't like the music; then suddenly gets overwhelmed, but while making the quick exit they catch fragments of conversations (somehow two words become three sentences), they can see people turning and staring without actually looking at them, they have twenty different mental images of themselves leaving the room, head filled with thoughts that are probably critical. When they invariably do the self-analysis later that day, and the next day, and the day after, they're left wondering how it was so easy to read other people, yet they have no clue why they got overwhelmed, and their slight social anxiety is multiplied by the hundreds of eyes that watched them leave. OMG what happens the next time they have to go out in public...
A not so clueless introvert would stand by the door for a few minutes, before going to the bathroom, then entering the room and finding one person they know and talking with them, before leaving after a while, getting a satisfactory self-review on the drive home.
Same person on acid would stand by the door for a while just watching people before maybe sitting down somewhere, noticing colours and the music, and the rush of thoughts and ideas going through their head, laughing at some of the ideas they have about what people are fighting about, before it becomes too much, so they head outside and stare at the sky for a while, but their head doesn't clear up like normal, so they try some breathing exercises, but there is still a rush of thoughts, so they go back to the music which is amazing and they feel better, so they find people they know and have strange conversations before they start getting overwhelmed again etc. They spend a couple of days afterwards relaxing, discarding the irrational thoughts that remain for a while, recuperating.
Almost everyone has different experiences from everyone else, and each time they take it. The strength varies so much, between you being able to be in public to totally dysfunctional. You might be an atheist and spend 6 hours sitting in your car in a parking lot listening to music, happy that God is chilling right in the middle of your head generating the best visualisations you've ever seen (actual time 2 hours). You might get lost in a botanical gardens, before being led to safety, almost in tears, by some ten year old because you couldn't see the concrete path two meters away. The same kid then opens a gate for you because you can't understand how to, the sign that says "Pull gate" is a mess of colours and you got distracted by your hand morphing into a windmill when you reached for the handle, walking is hard because you're not sure if you're standing but you seem to be moving north because you can feel the compass pointing that way...
This is just random info you can consider, actual advice given by lestoran and Simpy in previous posts.