Look up Mast Cells as well for your research. These cells sometimes overact and release too much histamine. They rise to the surface of skin, instead of staying in check in the immune system, including intestinal wall. Quercetin is used to keep these particular cells in check giving relief from Asthma, urticaria, Rhinitis, aches and pains mad digestive orders. Mast cells also make themselves at home by attaching to your nerve endings and being responsible for stress, anxiety and sometimes depression. Again, quercetin apparently clears this. I have all these ailments. I have just started taking Quercetin with nettle Tea. I'll give it a month...