Historical reference: Do not rely on this information. It is very old. About this collection
Tonics are remedies which favourably influence the nutrition of the body, improving appetite and digestion. Change of air, exercise, and baths are the most valuable tonic remedies. Certain drugs possess tonic properties, either in virtue of their action upon the digestive system, as in the case of calumba, gentian, quassia, and the like, or by their influence in improving the condition of the blood (preparations of iron having a remarkable influence of this kind), or by their general effect as "alternatives" and general tonics, producing improvement of nutrition.