The roots are used. Dried ginseng can be chewed, or it can be powdered and brewed as a tea. It will be just as potent as eating the roots, and have the same medicinal effects and side-effects.

To make the tea, put about 1 teaspoon dried root into into a cup, pour over some boiling water, steep for 10-15 minutes, and strain out the powder (coffee filters are good for this.)

As far as I know, the root is the only part of the plant which is edible. Until you or I or someone else who posts here learns to the contrary, do not on any account use other parts of the plant for any purpose.

Harvest the root in autumn when the above-ground parts die back. when the plant is at least 4 years old, and preferably when 5-9 years old. Wash as soon as possible, but do not scrub. Use it when it has dried thoroughly, after about a month. Dry in shade, turning frequently, until they just start to snap when you bend them, usually after about a month. Seeds may be kept in damp sand for 1 year and used for replanting. If using the roots for tinctures or extracts, use the roots fresh. Use dried roots for pills and powders.

NEVER use ginseng as a beverage. As with all herbal teas, it is a medicine, and ginseng is more powerful than most, with many side-effects and contraindications. I always recommend using ginseng ONLY under the supervision of a qualified herbal or medical expert. It's not a herb to be used lightly. [The smallest amount of it gives me the jitters and keeps me awake in a most distressing way. Other people may react differently, but this is not an uncommon reaction to it. After a couple of experiences with it, I now leave it permanently OFF my agenda!]

Warning: Avoid coffee while taking ginseng. Avoid if suffering from high blood pressure, and if pregnant or breast-feeding. May cause over-stimulation and insomnia. Taking ginseng while suffering from a cold may worsen the symptoms. Do not take ginseng within 2 hours of taking vitamin supplements or Vitamin C. Long-term use may cause menstrual abnormalities and breast tenderness in some women. Excessive use may cause headaches. Not recommended for people suffering from acute inflammatory diseases or depression, or who are under 40 years of age.