[header] How to make and use an onion poultice for congestion [title] Purchase two medium-sized onions. [step] Red onions typically contain the most quercetin. However, all onions have some of the antioxidant and have demonstrated expectorant properties for those with congestion. 
Therefore, two red onions may be preferable, but any two medium-sized onions will do. [substeps] Onions are known to contain quercetin (an antioxidant) and phytochemicals, both of which may help the body by breaking up the mucus in the chest and head.