Wild Indigo (Baptisia tinctoria) has a history of traditional use in herbal medicine, particularly among Native American and early European settlers in North America. Historically, it was used to address various infections and as a general immune stimulant. Its roots were often employed in decoctions and tinctures to help the body resist infections, especially those involving the upper respiratory tract. This traditional use extended to ailments such as sore throats, mouth ulcers, and occasionally sinus-related complaints, although its primary focus was not specifically on the sinuses but rather on general immune support and infection control.

Scientific studies on Wild Indigo are limited and largely preclinical. The available research suggests it has immunomodulatory and mild antimicrobial properties, likely due to the presence of alkaloids and other phytochemicals. However, there is little direct clinical evidence supporting its use specifically for sinus health or sinus infections. Most contemporary herbal references cite Wild Indigo as part of traditional formulas for immune and upper respiratory support, sometimes including conditions affecting the sinuses.

In summary, while Wild Indigo is traditionally used as a supportive herb for immune function—which could indirectly benefit sinus health—the evidence for its efficacy in supporting the sinuses specifically is based more on historical practice than on scientific validation.