Yellow card is used externally. Before use, the mustard packet (4 cells) is shaken to distribute the powder uniformly throughout the cells of the bag. Place the bag for 15-20 seconds in warm water, then put the skin on the porous side of the paper. Close with a dry dense cloth, press firmly against the body. The time of the procedure is 5-20 minutes (before the emergence of persistent redness) depending on the age of the patient and the sensitivity of the skin; in children - 2, 3, 5 or 10 min, depending on the child's age, irritating effect and individual sensitivity of the child.If you feel a strong burning sensation, you must loosen the mustard plaster to the body for a while or remove it.