Generally, manufacturers of herbal remedies and dietary supplements do not need FDA approval to sell their products. Just like a drug, herbs and supplements can affect the body's chemistry, and therefore have the potential to produce side effects that may be harmful. There have been a number of reported cases of serious and even lethal side effects from herbal products. Always check with your doctor before using any herbal remedies or dietary supplements.
The following is of special concern for people with glaucoma:
Bilberry, a European blueberry (Vaccinium myrtillus), is sold in natural food stores as a glaucoma remedy. Studies indicate that it may help some people improve night vision and glare, but it is not at all effective in preventing or treating glaucoma.