Buddha's Hand (Citrus medica var. sarcodactylis) is primarily used in Traditional Chinese Medicine (TCM) for digestive complaints, including nausea and vomiting. In TCM, Buddha's Hand—known as "Fo Shou"—is classified as an herb that regulates Qi (energy flow), particularly in the stomach and spleen. It is believed to relieve "Qi stagnation," which is associated with symptoms like abdominal distension, belching, poor appetite, nausea, and vomiting.

Historical records and classical TCM texts describe its use for harmonizing the stomach and alleviating digestive discomfort. Typically, the dried rind is used in decoctions or tinctures, often combined with other herbs to enhance its effects on indigestion and nausea.

However, scientific research on Buddha's Hand for the treatment of nausea and vomiting is limited. While some studies have explored the fruit’s phytochemical properties—such as its content of flavonoids, limonoids, and essential oils—clinical trials or robust pharmacological studies specifically evaluating its antiemetic effects are lacking. Most modern references to its use for nausea derive from traditional practice rather than empirical data.

In summary, the use of Buddha's Hand for nausea and vomiting is justified by traditional evidence within the TCM framework, but scientific validation remains minimal.