Vitamins are still safe to take after the expiration date. The expiration date is put there to show when the key ingredients have reached the end of their highest potency period. They can be safely consumed for 1 year after the expiration date.
The expiration date on vitamins usually tell you that after the mentioned date, the effectivity of whatever may have expired is already lost. It is not adviseable to still take vitamins past the expiration date.