The flower , which has the non-toxic pyrrolizidine alkaloid thesinine , has a sweet honey-like taste and as one of the few truly blue-colored eatable things , is often used to decorate dessert . . The flower , which contains the non-toxic pyrrolizidine alkaloid thesinine , has a sweet honey-like taste and as one of the few truly blue-colored edible things , is often used to decorate dessert .