Clinically, primary attention should be paid to prohibitions in medication, which include incompatibility, prohibition in pregnancy and abstinence from some foods when medicinal substances are administered.
Prohibited Combination of Medicinal Substances
- Prohibited combination means the quality is not suitable for combination of two or more medicinal substances or simultaneous administration as they are mutually repelled, resulting in strong toxic or side effects, or reduction or damage of effects. Among the “seven types of herbal combinations”, “mutual antagonism” and “mutual incompatibility fall in this category, which must be avoided in clinical use. The most noted and influential ones are the “eighteen incompatibilities” and “nineteen antagonisms” summarized during the Jin and Yuan Dynasties.
- Eighteen incompatibilities: Radix Glycyrrhizae is incompatible with Euphorbia Kansui, Euphorbia Pekinensis, Sargassum and Flos Genkwa; Aconitum Carmichaeli is incompatible with Bulbus Fritillariae Thunbergii, Fructus Trichosanthis, Rhizoma Pinelliae, Radix Ampepolopsis, and Rhizoma Bletillae; Veratrum Nigrum is incompatible with Radix Ginseng, Radix Glehniae, Radix Salviae Miltiorrhizae, Radix Scrophulariae, Herba Asari and Radix Paeonia Lactiflora.
- Nineteen antagonisms: Sulfer antagonizes Mirabilitum Depuratum; mercury antagonizes arsenic; Radix Stellerae Chamaejasmis antagonizes Lithargyrum; Croton Tiglium L. antagonizes morning glory; lilac antagonizes tulip; Radix Aconiti antagonizes rhinoceros horn; Radix Aconiti Kusnezoffii antagonizes rhinoceros horn; Mirabilitum Depurarum antagonizes Rhizoma Spargani; Cortex Cinnamomi antagonizes Halloysit; and Radix Ginseng antagonizes Faeces Trogopterori.
Note: The above are mutually repelled and must not be used together.
Each medicinal substance has its own specific nature for a specific condition, so when it is used clinically, its indication is within a certain range. For example, Herba Ephedrae, acrid and warm in property can induce sweating and release the exterior, or clear the lung, relieve asthma and increase excretion of urine. It is only indicated for asthma and coughing due to contraction of external wind and cold, an exterior excess syndrome without sweating or obstruction of lung qi. It is prohibited to use in patients with spontaneous sweating in an exterior deficiency syndrome, yin deficiency with night sweating, or asthma due to deficiency in the kidney and lung. Rhizoma Polygonati, sweet in taste and neutral in property acts to nourish yin, tonify the lung and invigorate the spleen and qi. It is mainly used in patients with deficiency in the lung and dry cough due to deficiency in the spleen and stomach, and insufficient kidney essence. Yet, it cannot be used in patients with deficiency and dampness in the spleen, cough with expectoration of excessive sputum, and cold in the middle and loose stools, because it is greasy, tending to retain dampness. In general, any medicinal substance has its own contraindications, so it is essential to use it with caution.