1.
by the use of chemicals
chemically fertilized
2.
with respect to chemistry
chemically different substances
The following are synonyms for 'chemically'. Click on any of them to get both Bibliodata's full list of common definitions and a further set of synonyms.
One of the reasons marijuana is illegal today because cotton growers in the 30s lobbied against hemp farmers -- they saw it as competition. It is not chemically addictive as is nicotine, alcohol, or caffeine.