Saffron Kesar is a spice derived from the flower of Crocus sativus, commonly known as the "saffron crocus". The vivid crimson stigma and styles, called threads, are collected and dried to be used mainly as a seasoning and colouring agent in food. Saffron has long been the world's most costly spice by weight. Health benefits of kesar milk- Protection Against Cold. Saffron is an effective tonic to treat cold and fever. Promotes Memory Retention. Relieves Menstrual Cramps. Helps Treat Insomnia. Good For Heart. May Help Treat Asthma and Allergies.