How many teaspoons is 100 mg?

One can calculate it easily. One teaspoon is approx. 5 GRAMS. Each Gram contains 1000 milligrams. Therefore one teaspoon is equivalent to approx. 5000 milligrams. 100 mg is approx 1/50 of a teaspoon.

If in milliliters:

One teaspoon is equal to 5 mg/5 ml therefore 100 mg or 100 ml is equal to 20 teaspoons. Let me further say you that mg means milligrams and ml means milliliters.