Cowspots..Most asthma is caused by Inflammation and Histamine so these supplements might help.Vitamin-C with Bioflavanoids and Quercetin are very good at clamping down on Histamine.
As for inflammation the Omega-3 fatty acids (fish/flax oil) and Evening Primrose oil is good for that. Also Tumeric and Ginger spices are very good for inflammation..
Later Cowspots.....