Nonetheless, when a certifying agency grants a hechsher to Vitamin C tablets, every ingredient, even those that are inactive, must be kosher. Numerous minerals and nutritional supplements are also definitely kosher. For example, copper oxide, psyllium husk, dicalcium phosphate, fennel seed powder, eucalyptus oil, menthol, and pure herbal leaves are always kosher. Many of these ingredients pose kashrus concerns. This lubricant used in most tablets is often derived from non-kosher animals.
Lactose is quite common in tablets, capsules, and homeopathic remedies.
Some additives are always permissible. For example, corn starch, which allows the active ingredient to quickly disintegrate and enter the blood stream, is halachically permissible. As with all Halacha, one should consult his Rav. The following is the Halachic ruling of Rabbi Moshe Heinemann Shlita , Star-K Rabbinic Administrator. Someone who is ill and whose life may be in danger.