Sichuan Lovage (Ligusticum chuanxiong, also known as Chuanxiong) is a well-known herb in Traditional Chinese Medicine (TCM), where it is primarily used to promote blood circulation and dispel wind to alleviate pain, especially in the context of headaches and menstrual disorders. In TCM theory, conditions like cold sores (herpetic lesions caused by HSV-1) may occasionally be associated with wind-heat or blood stasis, and formulas containing Sichuan Lovage might be prescribed to 'move blood' and 'clear wind' in certain presentations. However, the direct use of Sichuan Lovage specifically for cold sores does not have a strong historical precedent in either classical or modern TCM texts; its inclusion would typically be as part of a larger formula tailored to an individual's pattern, rather than as a primary or specific remedy for cold sores.

Scientifically, there is little to no evidence that Sichuan Lovage or its active constituents possess direct antiviral activity against herpes simplex virus (HSV-1), the causative agent of cold sores. While some studies have explored the general anti-inflammatory and antioxidant properties of Ligusticum chuanxiong, no clinical trials or robust preclinical studies have established its efficacy for treating or preventing cold sores. Thus, its use for this condition is justified mainly by tradition, and even then, only indirectly.