Plant Characteristics and Medicinal Value of Ajuga decumbens

Ajuga decumbens is a perennial herbaceous plant in the genus Ajuga of the Lamiaceae family, also known as Ajuga, blood-dispersing herb, and blood-breaking cinnabar, so named because the whole plant is densely covered with white soft hairs. It mostly grows in moist areas such as field edges, roadsides, and forest margins, and is relatively common in the Yangtze River basin and the provinces and regions south of it in China, making it a commonly used herbal medicine among the people.

The plant is generally not tall, with a four-angled stem that is often prostrate at the base and upright or ascending in the upper part; the leaves are opposite, mostly ovate or elliptic-ovate, with irregular coarse serrations along the edges. It blooms from spring to early summer, with small pale purple or blue-purple labiate flowers arranged in whorls, and the whole plant has a distinctive odor.

In terms of medicinal use, the dried whole plant of Ajuga decumbens is used as medicine. Traditional Chinese medicine considers it bitter in taste and cold in nature, with effects such as clearing heat and detoxifying, cooling blood and reducing swelling, and relieving cough and expelling phlegm. It is commonly used among the people for sore and swollen throat, cough due to lung heat, carbuncles and sores, and traumatic injuries. It should be noted that herbal medicine use emphasizes syndrome differentiation, and specific usage and dosage should be followed under a doctor's guidance; it is not advisable to take it on one's own in large amounts over a long period.

Many people confuse Ajuga decumbens with Prunella vulgaris, but in fact they are not the same plant. Prunella vulgaris belongs to the genus Prunella and uses its fruiting spikes as medicine, and its distinctive spicate infructescence is easy to recognize; whereas the notable feature of Ajuga decumbens is that the whole plant is covered with white down, and the whole plant is used as medicine. The two differ in source, morphology, and the effects they emphasize, so care should be taken to distinguish them when purchasing and using.