While taking illegal substances can lead to any number of unpleasant, dangerous or even fatal side effects, a phenomenon that often goes unremarked upon is the likelihood that drug abuse will cause bad breath.
A number of drugs can lead to bad breath, though each one's mechanism is slightly different. A study published at WebMedCentral noted that one of the worst drugs, in terms of dental damage done, is methamphetamines.
This class of stimulants causes what is commonly called "meth mouth." Between dental decay, chronically ground teeth, dry mouth and constricted blood vessels, methamphetamines can lead to severe periodontal disease, often with shockingly rapid tooth loss. All of this can cause terrible bad breath.
Cocaine use causes a similarly long list of dental problems, which, according to the study, includes "gingival lesions, bruxism [tooth grinding], excessive hemorrhage after tooth extraction...and [an] increased rate of periodontal disease."
Researchers also noted that heroin and marijuana can take their toll on oral health, leading to rampant halitosis. Besides brushing, flossing and using a specialty breath freshener, it is essential that drug users consider getting medical and psychiatric help as soon as possible.