jarrow is a good company in my experience, i'm sure this quercetin is quality and that it's just me. the capsule is of average size of youre used to supplements, and it doesn't taste bad or give and weird tasting burps or anything. if you open the capsule, caution that the powder stains. i knocked one star off not because of the product itself but because it seems as though it was not stored in ideal conditionsâ€"the powder in the capsules is clumped up which happens when exposed to heat/humidity. a common issue i have when ordering supplements from amazon. i took large doses of quercetin for many years with absolutely no side effects to help with mast cell activation syndrome, reproductive inflammation, and all the other things this stuff is good for. it was very helpful, particularly for mcas and terrible periods (pcos endo), and i was pleasantly surprised that it helped my migraines too! however, i eventually had to stop taking quercetin because my gastroparesis drastically worsened over time and made everything sit in my stomach for 20 hours which really does NOT go over well with literally anything, but especially quercetin in particular for me apparently. i got this to try to reintroduce it for the umpteenth time and had the same issue again. hopefully someday my gp improves and i can benefit from quercetin again. i haven't been able to find anyone else who has this reaction. plenty of others with gastroparesis (and myself before my gp worsened so much) have no issues with it, and for people whose gp/other digestive issues are caused or aggravated by mast cell disease quercetin can in theory help gi issues instead of causing them (it used to help like that for me, but mcas is far from the only contributor to my gp so i got worse anyway). many people with mast cell disease report tolerating it better if they start with smaller doses and slowly titrate up. it's worth a try and i still recommend it to my loved ones with allergies, debilitating periods, mast cell disease, and other inflammatory shenanigans, and my dad swears it helps his Diverticulitis and crohns/uc (he has mcas too). everyone is unique and i'm not a doctor, this is just my experience and that of others