Cornflower is an herb. The dried flowers are used to make medicine. People take cornflower tea to treat fever,constipation, water retention, and chest congestion. They also take it as a tonic, bitter, and liver and gallbladder stimulant. Women take it for menstrual disorders and vaginal yeast infections. Some people apply cornflower directly to the eye for irritation or discomfort. In foods, cornflower is used in herbal teas to provide color.