What was the main active ingredient in "Mrs. Winslow's Soothing Syrup" for children?

Mrs. Winslow's Soothing Syrup was a patent medicine first introduced in the 19th century and marketed to calm small children, clean teeth, freshen breath, and relieve constipation. Its colorful advertising, including trading cards and calendars, showed happy, peaceful babies cradled by beautiful new mothers.

Unknown to parents, each bottle contained a dangerous amount of morphine and alcohol. Patent medicines were treatments that could be purchased without a prescription. They were commercially protected by trademarks and rarely ever patented. Consumers did not know the contents of patent medicines, including the ones they gave their children.