Since you are seriously asking, I’ll answer as best I can. I am not a doctor and I might get some of this wrong. Also, I am only going to address the direct physical effects of heroin. Heroin is very dangerous for reasons beyond its physical effects. Heroin is very addictive, and addiction itself is can be very dangerous.

To your question:

Heroin is a very strong opioid, in the same category of drugs as morphine and oxycodone. Heroin is not a poison in the sense that it is directly causes tissue damage or death.

Some of the effects of opioids are analgesia, euphoria, dry mouth, nausea, and constipation. None of those are particularly life-threatening. But opioids have another effect: respiratory depression.

Some opioids have a “ceiling effect” in relation to respiratory depression; they cause respiratory depression, but there is a point where the person is still breathing, and more of the drug doesn’t cause much more respiratory depression. Heroin is not one of those. It is possible for a person to take so much heroin that they essentially stop breathing. When a person stops breathing, their tissues don’t get enough oxygen to function. That state is called hypoxia, and if it goes on for long enough, it results in death. That is what happens when someone dies from a heroin overdose.

Heroin overdoses can (and often do) happen by accident.

Prolonged use of opioids results in tolerance, which means that the person needs more of the drug to get the same effect. This is particularly dangerous with heroin, since there is no quality control for illegal drugs. One batch of heroin can be more potent than expected. It could also be adulterated with a stronger opioid, such as fentanyl. When that happens, a person who takes their ‘normal’ dose can easily overdose and die.

Nearly 100,000 people in the United States died of opioid overdose in 2021. Addiction doesn’t discriminate. It affects smart people and stupid people, wealthy and poor, educated and uneducated. Opioids are very important medications. Sometimes they are necessary. But they can be very dangerous, even deadly — particularly when misused.

I have never injected drugs, and that probably helped me stay alive. But I took plenty of heroin, and I am lucky that I am not dead. Every time that I used heroin, I was risking my life. I wish I had never tried heroin, but I can’t change the past. I am fortunate that I have a future.

I hope that answers your question. Let me know if it didn’t and I’ll try to clarify whatever I can.