Leta Derby Guthrie (pictured right, above), an alumna from Eta Chapter living in Tulsa, Oklahoma, was the mastermind behind the popular Phi Mu Toy Cart philanthropy program. A visit to a hospital in 1940 inspired Leta to begin the program. While walking through the children's ward, Leta noticed a little boy staring sadly out the window. When she asked him what was wrong, he said he wanted an automobile more than anything. Moved to help the sad, sick child, Leta headed to the nearest "dime" store and bought a toy automobile for the boy. Soon, she was bringing toys to more and more hospitalized children and Leta realized that she needed assistance. She brought the idea to the Tulsa Alumnae Chapter, who accepted the project, and then sought out the authorities at St. John's Hospital in Tulsa. The hospital administration eagerly accepted the idea and donated a metal tray cart, which the Phi Mus painted and decked out with toys, games, and books for the children. To the children's delight, Phi Mu volunteers rolled the cart throughout the children's ward three afternoons a week.
When Leta became President of District VIII a few years later, she began to tell other alumnae chapters about the Toy Cart program. Her idea quickly spread to Toledo, Cincinnati, Cleveland, and Lexington. In 1946, Leta introduced the subject of the toy carts at the National Convention, and the program was readily adopted as a national philanthropy project. Sadly, only a few months later, in October 1946 Leta Derby Guthrie died due to complications following a surgery. She did not live to see the national success of the Phi Mu Toy Cart program she created, which saw 46% of alumnae groups with a toy cart after just two years and would continue among some chapters, including her own Tulsa Alumnae Chapter, well into the 1980's and 90's.