My friend is suicidal, and cuts. He cut too deep one day and cut a vein. It was pretty ugly. It didn't do any initial damage, but I'm worried it might happen again, and he could end up in a bad conditions... I want him to stop but he won't... How do I deal with this?

You're obviously in a difficult situation, and unsure of what you can do to help him. I suggest doing some research on what can happen to him if he continues to cut and then sit him down when you are both alone and calmly tell him about what you found out and how you feel. Don't patronise him or make him feel like a bad person, but let him know that he isn't alone and that you care about him.

You probably feel like it's your responsibility to make him stop and to look out for his wellbeing, but the responsibility shouldn't fall completely on you. Although it probably isn't advice you will take- tell someone in your life how you feel maybe without mentioning the name of your friend. That person will be able to reassure you about things, and may be able to direct you to some sites that may help either you or your friend.

Look up some websites that are designed to help suicidal people and refer your friend to them, remember to be sensitive but firm. If the pressure and stress from being his friend gets too much, tell someone very close to you about what is going on. At the end of the day, you have to think about your mental health as well as his.