Bromoethane is a critical intermediate and a widely used ethylating agent in the pharmaceutical industry. It is primarily used in nucleophilic substitution reactions to introduce an ethyl group onto specific nitrogen or oxygen atoms in precursor molecules, thereby altering the pharmacological activity and metabolic stability of drugs. It is a key raw material in the synthesis of the anti-asthma and anti-allergy drug ketotifen, the central nervous system stimulant nikethamide, and various barbiturate sleeping pills. In addition, it is also used in the production of insecticides, herbicides, and fungicides.