this is what web md says about the 100mg and it doesn't say anything about being too high doses
This product is a combination of B vitamins used to treat or prevent vitamin deficiency due to poor diet, certain illnesses, alcoholism, or during pregnancy. Vitamins are important building blocks of the body and help keep you in good health. B vitamins include thiamine, riboflavin, niacin/niacinamide, vitamin B6, vitamin B12, folic acid, and pantothenic acid.
How to use Vitamin B Complex-100 Oral
Take this medication by mouth, usually once daily or as directed. Follow all directions on the product package. If you are uncertain about any of the information, consult your doctor or pharmacist.
If you are taking chewable tablets, chew the tablet thoroughly before swallowing.
If you are taking a timed-release capsule or tablet, swallow it whole. Do not crush, chew, or break the capsule/tablet. Doing so can destroy the long action of the drug and may increase side effects.
If you are taking a liquid product, use a medication-measuring device to carefully measure the dose. Do not use a household spoon.
Take this medication regularly in order to get the most benefit from it. To help you remember, take it at the same time each day.