A nightmare is a dream that causes an unpleasant and overwhelming state. It occurs while we sleep and can manifest differently in each person.
Nightmares occur for various reasons, mainly social, physical and emotional stress being to blame.
Also, people who eat more at dinner and late night may have bad dreams bringing them an ailment that can occur throughout the next day.
In this case, an efficient natural remedy is the tea of valerian root. It has soothing properties, dispelling nightmares if you drink two hot cups before you sleep.