Si Gua Luo, the dried fibrous skeleton of the mature luffa gourd, is best known for its gentle ability to open blocked channels throughout the body. It is most commonly used for joint and muscle pain, chest discomfort, and to help promote breast milk flow in new mothers. Its action is mild, so it is usually combined with other herbs rather than used alone.

'Unblocks the channels and collaterals' (通络 tōng luò) is the primary action of Si Gua Luo. Its physical structure as a network of fibrous vascular bundles inside the luffa fruit gives it a natural affinity for the body's own network of channels and collaterals. It gently opens blocked pathways, which makes it useful for joint stiffness, muscle pain, and conditions where circulation through the smaller branches of the channel system is impaired. This is the go-to action when pain or stiffness results from Wind-Dampness lodging in the channels.

'Invigorates Blood' means Si Gua Luo helps to move stagnant Blood through the vessels. Because it enters the Liver channel, it is often used for chest and flank pain caused by Qi and Blood stagnation. It also promotes lactation ('promotes the flow of breast milk') by unblocking the breast's network vessels. This is why it is a commonly used herb for insufficient milk supply or painful breast swelling after childbirth.

'Dispels Wind' refers to its ability to drive out Wind as a pathogenic factor, particularly Wind-Dampness that causes joint pain and muscle cramping. Its action is gentle, so it is typically combined with stronger Wind-dispelling herbs in formulas for rheumatic conditions.

'Transforms Phlegm' means Si Gua Luo can help clear Phlegm accumulation, particularly in the Lungs. When Lung Heat generates thick, sticky Phlegm causing cough and chest pain, Si Gua Luo can be combined with Phlegm-resolving herbs to open the chest and ease breathing.