Quercetin is a flavonal found in dill, cilantro, fennel, and many other plants.
Links to Plants Containing Quercetin
The listings of research below represents a compilation of scientific articles found on the topic, with a very brief overview description of each article/study. This compilation of research articles does not necessarily imply that there are adequate results to demonstrate safe and/or effective human use of any herb listed.
Naringenin and quercetin from citrus fruits inhibited toxins in cigarette smoke. From: Bear, W. L., & Teel, R. W. (1999). Effects of citrus phytochemicals on liver and lung cytochrome P450 activity and on the in vitro metabolism of the tobacco-specific nitrosamine NNK. Anticancer research, 20(5A), 3323-3329.