What to do if someone has a bad trip?

Always make sure that you are and remain safe yourself. If you are in danger, you cannot help the person in need.
Find a quiet place with the one who is having a hard time. Don’t try to deny that he/she is having a bad trip. Try to reassure him/her: he/she has taken drugs and the effects and thus the bad trip always wear off. Ask the person about what they are experiencing and try to talk the trip on a positive side without downplaying it. For example, by giving a positive meaning to the things he/she sees. Try to do things that make him/her feel comfortable, such as moving or singing. See if it makes sense to talk about pleasant things. Distraction can also help, for example by drawing. Let your voice sound calm and reassuring.
Make sure that the user does not end up in dangerous situations such as traffic. Call emergency services if it becomes unsafe for the user or his environment or if the bad trip is too intense to solve it yourself.