[[Fil:2,3,7,8-tetrachlorodibenzo(b,e)(1,4)dioxine 200.svg|thumb|300px|Strukturen af en dioxin: 2,3,7,8-tetraklordibenzo-p-dioxin (TCDD)]]
'''Dioxin''' er en samlebetegnelse for en gruppe [[klor]]holdige [[gift]]stoffer som dannes under forbrænding af [[organisk kemi|organisk]] materiale så længe der er [[klor]] til stede. Dioxin er meget skadelig for mennesker og dyr - men ikke planter da det ikke optages via rødderne; men planterne kan optage dioxin fra luften, hvorefter de skades.<ref>[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2788749/ J Environ Sci Health C Environ Carcinog Ecotoxicol Rev. 2009 Oct; 27(4): 197–211, ncbi.nlm.nih.gov: An Overview of the Effects of Dioxins and Dioxin-like Compounds on Vertebrates, as Documented in Human and Ecological Epidemiology] Citat: "...Research utilizing extensive laboratory species – including fishes, amphibians, turtles, birds, mice, rats, hamsters, guinea pigs, rabbits, dogs, and non-human primates -- has reiterated the observations made in the wild and in human epidemiologic studies, and demonstrated that the effects of this class of chemicals are not limited to specific species or unusually sensitive strains...", [https://web.archive.org/web/20190713112855/https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2788749/ backup]</ref><ref>[https://phys.org/news/2008-07-dioxin-soil-tissues-long-term-biosolids.html July 14, 2008, phys.org: Dioxin risk in soil and plant tissues after long-term biosolids application] Citat: "...Dioxins were not detected in the corn grains. Only trace levels were found in the corn stover, and there was no statistical difference between the control and the biosolids-amended plots. These observations suggest that dioxins from land application of biosolids do not pose any risk to human health or the environment, if biosolids are land applied according to the USEPA regulations...", [https://web.archive.org/web/20190713113333/https://phys.org/news/2008-07-dioxin-soil-tissues-long-term-biosolids.html backup]</ref> 
Under vietnamkrigen blev det brugt som plantegift i tætte jungleområder. Giften fører over lang tids eksponering til øget risiko for [[kræft]], reproduktionsforstyrrelser og andre [[hormonforstyrrende|hormonforstyrrelser]], nedsættelse af [[immunforsvar]]et og [[neurotoksi]]ske effekter.
Kemi