In Traditional Chinese Medicine (TCM), Jiang Xiang belongs to the 'Herbs that invigorate the Blood' category. Like the name indicates these herbs tend to stimulate the Blood flow. In TCM they're used to help the circulation of Blood in cardiovascular conditions or menstrual irregularities as well as to treat acute pains caused by Blood Stagnation. They can also be used to treat Blood Stagnation when it causes certain tumors, cysts and hardened clots.
Furthermore Jiang Xiang is Warm in nature. This means that Jiang Xiang tends to help people who have too much 'Cold' in their body, although with less effect than a plant that would be Hot in nature. Balance between Yin and Yang is a key health concept in TCM. Those who have too much Cold in their body are said to either have a Yin Excess (because Yin is Cold in nature) or a Yang Deficiency (Yang is Hot in Nature). Depending on your condition Jiang Xiang can help restore a harmonious balance between Yin and Yang.
Jiang Xiang also tastes Pungent. The so-called 'Five Phases' theory in Chinese Medicine states that the taste of TCM ingredients is a key determinant of their action in the body. Pungent ingredients like Jiang Xiang tends to promote the circulations of Qi and Body Fluids. That's why for instance someone tends to sweat a lot when they eat spicy/pungent food.
The tastes of ingredients in TCM also determine what Organs and Meridians they target. As such Jiang Xiang is thought to target the Spleen, the Stomach and the Liver. In TCM the Spleen assists with digestion, Blood coagulation and Fluids metabolism in the body. The Stomach on the other hand is responsible for receiving and ripening ingested food and fluids. It is also tasked with descending the digested elements downwards to the Small Intestine. The Liver is often referred as the body's "general" because it is in charge of regulating the movements of Qi and the Body Fluids. It also takes a leading role in balancing our emotions.