Just to let you know of a few cures that periwinkle flower work. My mother is from Cuba and most of the remedies when i was a kid were from plants i used to make fun, especially taking periwinkle flowers boiling them and used as an eyewash for eye infections. She said the white flower periwinkle, but who knows if the other colors work. But let me tell it works and now i found out the there is chemotherapy for leukemia made from this flower so i guess mom was right. Also used as a mouth gargle for strep.