n-Butylidenephthalide is a naturally occurring phthalide compound, commonly found in medicinal plants such as Angelica sinensis (dong quai). It is supplied as a high-purity analytical reference substance (≥98%) for use in pharmaceutical research, quality control, and analytical chemistry. This specialty chemical is primarily recognized for its potential therapeutic applications in traditional medicine and modern pharmacology, with studied neuroprotective, anti-inflammatory, and anti-cancer properties. In traditional Chinese medicine, it is used to improve blood circulation and alleviate symptoms related to menstrual disorders and cardiovascular conditions. Recent studies have explored its ability to inhibit cancer cell growth, positioning it as a candidate for cancer therapy. Its neuroprotective effects also suggest applications in treating neurodegenerative diseases like Alzheimer's disease. Ongoing research aims to elucidate its mechanisms and broaden its medicinal uses.