Ku ding tea (Chinese: pinyin, kunding chá; literally "bitter nail tea") is a particularly bitter-tasting Chinese tisane which due to their similarities in appearance is derived from several plant species. Two most common plants used to make Ku Ding tea, being the wax tree species Ligustrum robustum and the holly species Ilex kudingcha plant, the former being more commonly grown in Sichuan and Japan while the latter is most commonly grown and used in the rest of China.

Ku Ding Cha is a beverage tea consumed in China as an alternative to the more common, ordinary green tea. The standard Chinese tea, from Camellia sinensis, is known as cha, and this term is then applied to other herbs that are consumed in a similar manner. Ku Ding describes this particular beverage tea: ku means bitter, which aptly describes the initial taste, and ding is a Chinese character that looks like a spike, depicting the appearance of the dried, long leaves when they are twisted into a narrow nail-like piece; they can also be formed into balls or rolls. The herb name is often written as a single transliterated word-kudingcha-and is sometimes misspelled without the g, as kudincha.

Ku Ding Cha was described in the Bencao Gangmu Shiyi (1765), originally called Dong Qing, which refers to the fact that it is an evergreen tree (dong means winter, or written another way, frozen, and qing means green; it is the tree that stays green through the winter). This term, being rather general, led to some confusion about source materials, two groups of plants were being utilized for the tea: the holly (species of Ilex) and the wax tree (species of Ligustrum). Today, it is estimated that more than 90% of the Ku Ding Cha used in China is from an Ilex, mainly Ilex kudingcha (though other Ilex species, such as Ilex latifolia, may be used), while several species of Ligustrum are substituted in Sichuan Province and in Japan. Both the holly and wax tree are evergreens, their leaves have a somewhat similar appearance, and the wax insect that feeds off the wax tree is also found occasionally on the holly. The leaves of Ilex kudingcha are long, slim, without the points common to other holly plants, and somewhat rubbery in texture.

The traditional Chinese medicinal properties associated with Ku Ding include its ability to disperse wind-heat, clear the head and the eyes, and desolve toxins, thus being used for common cold, rhinitis, itching eyes, red eyes, and headache. It is also said to calm fidgets and alleviate thirst, especially when one is suffering from a disease that causes fever or severe diarrhea. It transforms phlegm and alleviates coughing, thus used in treating bronchitis. It is said to invigorate digestion and improve mental focus and memory.

Some research may suggest that the herb, derived from either Ilex or Ligustrum, promotes blood circulation, lowers blood pressure, and lowers blood lipids, including cholesterol. It has the reputation of preventing deterioration of the heart and brain function and maintaining proper body weight. It has also been found that Ku Ding tea made from L. robustum has similar anti-oxidative effects to green tea in addition to other anti-inflammatory properties.

The experience of drinking the tea is somewhat unusual. The taste of the tea is a pure, distinctive bitter, which, at first, would seem to make it undesirable. But, there is also an underlying sweet taste, one which becomes pronounced once the bitter wears off, a moment after taking a sip of the tea. It doesn't take too long to become accustomed to the taste and then find it attractive, in much the same way that coffee and other bitter drinks are desired. The strength of the tea can be adjusted to one's liking. It takes only a few spikes, typically 3-5 of them, to make a pot of tea for one person; hot water can be added again to the leaves, even several times, to make more tea.

Rinse tea cup and teapot with hot water. Use only 1 or 2 sticks for every 150ml of water. Steep tea leaves in hot water at 80°c (176°F) to 90°c (194°F) for 1 minute for the first and second brewing. Gradually increase steeping time and temperature for subsequent brewing.

A product has been developed that combines Ku Ding Cha with momordica, chrysanthemum, gardenia, imperata, morus leaf, and other herbs, and is used for clearing heat. It is recommended for counteracting overheating during the summer, for treating sore throat, alleviating the effects of consuming alcohol or smoking cigarettes, and resolving other hot-type conditions. Another popular combination is ginkgo leaf (Yin Xing Ye) with Ku Ding Cha (the combination called Yin Xing Ku Ding Cha). This emphasizes the circulation promoting and memory enhancing effects of both herbs. For example, a tea of this mixture is produced under the Xinquan brand, manufactured by Guizhou Haoli Industry, in Guiyang City, Guizhou.