Saffron (Crocus sativus) is a plant. The dried thread-like parts of the flower (stigmas) are used to make saffron spice, food coloring, and medicine. Saffron extract contains chemicals that might alter mood, kill cancer cells, decrease swelling, and act like antioxidants. It can take 75,000 saffron blossoms to produce a single pound of saffron spice. Saffron is largely cultivated in Iran and harvested by hand. It's one of the world's most expensive spices.