Siler (commonly referring to Fang Feng, or Saposhnikovia divaricata) is a well-known herb in Traditional Chinese Medicine (TCM). It has been historically used for centuries to "release the exterior" and expel "wind," which in TCM includes symptoms such as chills, fever, and body aches generally associated with early-stage colds or influenza. Fang Feng is often included in classical herbal formulas, such as "Yin Qiao San" or "Chuan Xiong Cha Tiao San," which are prescribed for conditions presenting with chills and fever. Its use is based on the TCM theory that certain herbs can help expel pathogenic influences from the body.

From a scientific standpoint, there is limited direct clinical evidence for Siler’s efficacy in treating chills specifically. Some modern pharmacological studies have shown that Saposhnikovia divaricata contains chromones and other compounds with anti-inflammatory and immune-modulating properties, but these findings are preliminary and do not directly validate its use for chills. The herb’s continued use for chills is thus primarily rooted in traditional practice rather than rigorous scientific validation. Most authoritative pharmacopoeias and reviews acknowledge the historical use of Siler for symptoms like chills and fever, but stress the need for more robust clinical trials to confirm its specific effects.