Tonic prescriptions refer to those composed chiefly of tonic drugs, which act to invigorate qi, blood, yin and yang of the human body, and are indicated for various deficiency syndromes.
 
Since syndromes of deficiency include four types, namely qi deficiency, blood deficiency, yin deficiency, and yang deficiency, and the first two types are concomitant to each other, tonic prescriptions are accordingly subdivided into five categories. They are prescriptions for invigorating qi, those for nourishing blood, those for invigorating both qi and blood, those for invigorating yin and those for invigorating yang.
 
Prescriptions for invigorating blood comprise drugs of nourishing blood and invigorating deficiency, and are suitable for blood deficiency of the heart and liver. Prescriptions for reinforcement of both qi and blood consist of drugs with the effects of benefiting qi and nourishing blood and are applied to deficiency syndrome of both qi and blood. Prescriptions for invigorating yin are mainly composed of drugs able to nourish yin and benefit essence, and used to treat yin deficiency of the liver, kidney and lung. Prescriptions for invigorating yang are mainly composed of drugs capable of warming and reinforcing kidney-yang and used to treat yang deficiency of the kidney.     
   
Tonic prescriptions should not be applied for long time because they are mostly strong and greasy and apt to affect the stomach. Besides they should be used carefully in cases with usual deficiency of the spleen and stomach, or with poor appetite and loose stool. In such a case, it is necessary to add some drugs capable of strengthening the spleen and stomach and regulating qi to promote transportation and transformation. For patients with deficiency syndrome and intolerance of tonics, it is advisable to regulate the spleen and stomach before tonic prescriptions are given. These prescriptions should be decocted for a longer period with mild fire and taken before meals or with an empty stomach to promote the absorption of the drugs.