When you put garlic under your pillow the garlic under your pillow is supposed to help you fall asleep and stay asleep.
Garlic under your pillow has been used as a cure for insomnia for years and some people do say it works to help them fall asleep fast and stay asleep.
Garlic contains sulfur compounds which are supposed to help you fall asleep and act as a calming affect and when you're calm and relaxed you can fall asleep faster and stay asleep.
The aroma of the garlic is supposed to have a calming affect on you as well.
I have never tried garlic under my pillow before but I will have to try it sometimes when I have trouble sleeping.
My sister says that she falls asleep better when she has garlic under her pillow but just make sure you don't leave the garlic under your pillow too long or it will rot.