Boa constrictors are not poisonous. They are like the name states. Constrictors. When they kill their prey they bite it and pull it close to them. Then they wrap their body around their prey and constrict until their prey suffocates.
No they are not poisonous. They kill their prey by wrapping their body around them and squeezing them(constricting) til they die. However, they do have teeth that can hurt pretty badly if they bite you.
Snakes kill their prey either by poison (injecting venom) or by constriction (suffocation by squeezing). The answer to your question should be self evident if you are talking about boa constrictors, because boa constrictors kill by constriction.
No they are harmless.I have a Red-Talied Boa.He just looks poisonous