Piper retrofractum, commonly known as Javanese long pepper, has a history of use in traditional medicine systems in Southeast Asia. It is traditionally employed for a variety of ailments, including digestive issues and respiratory complaints. In some ethnobotanical records, Piper retrofractum is used to address symptoms similar to those of sinus infection, such as nasal congestion and cough. The rationale in traditional use is often based on its pungent and warming properties, believed to help clear mucus and support the respiratory system.

However, the scientific evidence specifically supporting the use of Piper retrofractum for sinus infections is minimal. While some laboratory research has explored the antimicrobial and anti-inflammatory properties of Piper retrofractum extracts, these studies are preliminary and do not directly address sinus infections in humans. There are no clinical trials or robust pharmacological studies that validate its efficacy for sinusitis or related conditions. Therefore, the use of Piper retrofractum for sinus infections is primarily justified by tradition and anecdotal reports, rather than by scientific validation.