All parts of the Crocus (including the corms) are toxic in varying degrees and should be avoided. The true Crocus (Crocus spp.) can cause stomach upset and vomiting, while the Autumn Crocus (Colchicum autumnale) is highly toxic and should be avoided at all costs. See Autumn Crocus.
N.B. The true Crocus has 3 stamens and 1 style with 3 stigmas, whereas Colchicum autumnale has 6 stamens and 3 styles.