Herbicides, also commonly known as weed killers, are used to kill unwanted plants. Selective herbicides kill specific targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic "imitations" of plant hormones. Herbicides that are used to clear waste ground, industrial sites, railways and railway embankments are non-selective and kill all plant material that they come into contact with. Smaller quantities are used in forestry, pasture systems, and management of areas set aside as wildlife habitat.

Herbicides are widely used in agriculture and in landscape turf management. In the U.S., they account for about 70% of all agricultural pesticide use. Herbicides can also be transported via surface runoff to contaminate distant water sources which will be consumed by people, but also pets and wildlife. The bird population seem particularly affected by the wide use of herbicides. Herbicides have widely variable toxicity. In addition to acute toxicity from high exposures, there is concern of possible carcinogenicity as well as long-term problems like contributing to Parkinson's disease. Research suggested that such contamination results in a small rise in cancer risk after exposure to these herbicides. Triazine exposure has been implicated to increased risk of breast cancer.

In addition to health effects caused by herbicides themselves, commercial herbicide mixtures often contain other chemicals, including inactive ingredients, which have negative impacts on human health. For example, Roundup contains adjuvants which, even in low concentrations, were found to kill human embryonic, placental, and umbilical cells in vitro. One study also found that Roundup caused genetic damage, but that the damage was not caused by the active ingredient. This is interesting since Monsanto, the company that makes Roundup said "it is safer than table salt and practically non-toxic to mammals, birds, and fish".

Because of the large number of herbicides in use, there is significant concern regarding health effects. If you like that amazing lawn with plush grass and no weeds, you can assume there are herbicides involved. You might be spraying the week killers yourself or you might have someone else doing it. Either way, try to avoid contact with that grass, particularly direct skin contact.

Dr. DeHaan believes that ingesting honey, no matter how "natural", is no longer a good alternative sweetener because of the contamination of herbicides. When bees feed from flowers that have been sprayed, the toxins will naturally be found in the honey. Organic sugar, maple syrup, stevia and xylitol are all considered better choices for sweeteners.