How did Sai Baba's Udi prove effective for people suffering from insomnia or sleeplessness?

Chapter 33 of the Sai Satcharita provides two clear examples of how Udi was used to cure sleeplessness. In one instance, a friend of Hari Sitaram Dixit had been unable to sleep for eight days, and even a doctor's medicine was ineffective. Mr. Dixit gave him Baba's Udi and instructed him to take it. After taking the Udi just once, the man reported the very next day that he had slept soundly through the entire night. In a similar case, a friend's child who had not been able to sleep for two months was taken for Baba's Darshan in Shirdi. The account states that on that very night in Shirdi, the child slept well and continued to sleep soundly every night thereafter.