Vitamins are essential nutrients. They are required at specific quantity only, for optimal function of various systems of human beings. Most of the Vitamins are available as a part of our daily food like Bread, Fruit, Cereals, Fish etc. So for an ordinary person, it is not required to take extra-dietary Vitamins.
Vitamin deficiency is shown by certain signs and symptoms that are perceivable to your doctor. When doctor confirm the deficiency clinically and by specif tests, he advise Vitamins in the form of medicine as per the requirement.
When vitamins are consumed beyond the require dose, yes it cause some side effects that may be dangerous some times. It is not the matter for single or multi pack vitamins, any thing beyond required can be deleterious effects to life.
These Q&A’s are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.