There are however certain herbal concoctions which can enhance trance, meditation and spirit work and many witches find these very helpful. Normally such herbs help to produce a meditative state and some have halluciogenic properties. But the key is to use them to unlock an understanding of the other worlds and the depths of your own mind. The typical "acid trip" would have little value for a witch as it is just a fooling of the mind. That might be an interesting experience but it has very limited magical value.
I completely understand the inclination to experiment with your own mind but in all honesty
there is very little that a drug can do with your mind that you can't achieve yourself with the right focus. I've taken drugs for medical and recreational purposes myself but it always feels a bit too much like the easy way to reach a state of mind. Drugs are the instant gratification of the modern age. I prefer to put the mental work in to achieve the state of mind I desire. Its a balancing act of course, it probably isn't worth the mental effort to cure my own headache rather than pop a paracetamol, equally it isn't worth the addiction risks in taking high level morphiates to generate calmness and wellbeing.
Its also important to consider the wider implications of drug taking. The legality is important (of course many recreational drugs are NOT illegal but many are.) As a witch I can think of nothing that would scupper my peace of mind more than being banged up in prison. The affect on my craft would be disastarous. So breaking the law is not a risk worth taking.
Then there are the heath implications. Some drugs react with herbs (think St John's Wort and the contraceptive pill!), some react with other drugs, some react with certain states on mind, many react badly to alcohol. Is it worth spending so much time working on your spiritual health to wreck it all by failing to consider your physical health?
I'm not saying all witches do or all witches don't. Everybody draws the line where they believe it is right for them. What I am saying is consider the law, consider the health implications and think about why you want to do it. The mind is a powerful tool. However you want to feel, you can train your mind to get there without chemicals.