Baby can get a bag over his mouth and nose and suffocate. Throw broken balloons out immediately. If you can, move cleaning supplies to a high place. Put childproof locks on cupboards with dangerous chemicals. Children drink things just to try them, even if they taste bad.
Some house plants are poisonous.
If you have a party, pour left-over drinks down the sink. It takes very little alcohol to poison a child. Cigarettes can also poison children who eat them. Medicine cabinets should lock. Don't take medicine in front of your child.