Petasines are compounds found in the plant Petasites hybridus, commonly known as butterbur. Butterbur extracts, standardized for petasines, have been investigated for their effects on the sinus and respiratory systems, particularly in the context of allergic rhinitis (hay fever) and migraine prevention. Several randomized, double-blind, placebo-controlled trials have demonstrated that butterbur extracts can reduce symptoms of allergic rhinitis, such as nasal congestion, sneezing, and itchy eyes. A 2002 study published in the British Medical Journal found butterbur extract to be as effective as cetirizine (an antihistamine) for hay fever, but with fewer sedative effects. Meta-analyses and systematic reviews have concluded that butterbur may have a modest beneficial effect in allergic rhinitis, although concerns about the safety of some butterbur preparations (due to potentially hepatotoxic pyrrolizidine alkaloids) remain.

The proposed mechanism involves inhibition of leukotriene synthesis and histamine release, reducing inflammation in the mucous membranes of the sinuses. The German Commission E has approved butterbur for use in treating allergic rhinitis. However, it is important to use only certified PA-free extracts to avoid liver toxicity. While the evidence is not overwhelming, it is stronger than for many herbal remedies, justifying a moderate rating for scientific support of petasines in sinus health.