Petasines are active compounds found in the plant Petasites hybridus (commonly known as butterbur). The use of butterbur extracts, standardized for petasines, has a long history in traditional European herbal medicine, particularly for respiratory conditions such as asthma, bronchitis, and allergic rhinitis. Modern scientific research has investigated the anti-inflammatory and antispasmodic effects of petasines, especially in the context of allergic and asthmatic responses that affect the bronchial system.

Several randomized, double-blind, placebo-controlled trials have shown that butterbur extracts can reduce symptoms of allergic rhinitis and may help in controlling bronchial hyperreactivity. The proposed mechanism involves the inhibition of leukotriene synthesis and modulation of histamine release, both of which play central roles in bronchial inflammation and constriction. A notable study published in Clinical and Experimental Allergy (2004) found butterbur extract to be as effective as cetirizine (an antihistamine) in managing allergic symptoms without causing sedation.

While most research has focused on allergic rhinitis, some studies have extended findings to asthma and bronchitis, suggesting potential benefits for broader bronchial support. However, it is important to note that only extracts free of pyrrolizidine alkaloids (PAs) are considered safe for use, as PAs are toxic to the liver. Overall, the evidence base for petasines in bronchial support is moderate to strong, with most studies supporting symptomatic relief rather than disease modification.