From a medieval manuscript
Herbs can be administered in a number of different ways, and Herbalists can use any part of a plant; roots, bark, seeds, leaves, flowers etc. They can be compounded with other herbs to make complex potions, pills, and ointments. Although the methods for making medicines are simple it should be left to the expert! Dosages may seem vague but it has to be remembered that the concentration of active chemical in natural plants varies widely anyway. The source for the following is taken from 'Culpeper's Herbal Remedies' (arranged by Mrs C.F. Leyel).
INFUSIONS, TEAS OR TISANES:
Infusions are designed for easily absorbed herbs and can simply be made by pouring a pint of boiling water onto an ounce of herbs, then straining away the herb. Dosage for adults; one wineglass full, tablespoon for children.
When the active ingredients are found in hard and woody substances such as roots, wood or bark, a decoction is made. Half an ounce of broken up root can be simmered in a pint and a half of water, until a third of the liquid has boiled away, and strained while still hot. Dosage as above.
Alcohol, vinegar and glycerine are better solvents than water for many plants. For an alcohol-based tincture, place finely ground herb in 40 per cent proof alcohol such as vodka, and keep in a warm place for 2 weeks. Place lid on tightly. Shake every day. Decant liquid, wring out in muslin cloth, and store in dark bottle.
Many herbal medicines are ghastly, and so the taste was disguised as a syrup or made more 'Toothsome' as Culpepper reported. To make a syrup, simply pour a pint of water on 2lb of sugar. Stir until sugar dissolves, and the liquid boils. Take off heat.