Poisoning symptoms: dizziness, vomiting, etc. ?
Whether the Dutch beans are ripe or not can be judged by some methods: the bean sticks change from stiff to weak, the color changes from bright green to dark green, and there is no bean smell when eaten.
In order to prevent poisoning, you can use boiling water or hot oil to stir-fry it until it is discolored and cooked before it can be eaten safely.