Can earwax give reliable proof of drug use? Possibly. Forensic science is always innovating in its search for effective methods. Typically, forensic analysis for neuropsychotic drugs comes from blood and urine samples. But some drugs have such a short half-life that traditional tests aren’t always accurate, while other testing methods—saliva, sweat, hair and nails—can prove unreliable, with a high risk of contamination and a difficult collection process.

In the search for better methods, forensic scientists are now looking at the use of cerumen, commonly called “earwax.” Earwax is secreted from ceruminous glands, essentially a type of sweat gland. A broad range of drugs including ETOH (alcohol), amphetamines, cocaine, methadone, along with psychotropic and antiepileptic (anti-seizure) drugs are found in sweat, often in higher concentrations than in blood. The logic follows that if these substances can be seen in sweat, then they should also show up in cerumen.

In a Brazilian study, cerumen samples were obtained from 17 individuals that used antiepileptic and antipsychotic drugs. Many of the drugs tested (such as phenobarbital, clonazepam, lamotrigine, valproic acid, and carbamazepine) were found in significant concentrations in the sampled cerumen. Interestingly, phenytoin was detected and quantified in an individual who had stopped using the drug two months prior to the study. Cerumen testing is promising not only for evaluating recent drug use, but also for drug use from previous months.

Familiarity with forensic science and its technological advances isn’t only for the scientific community, but also for the legal community. Trending issues in substance abuse testing are valuable information for both prosecuting and defense attorneys. Earwax may just become part of every criminal attorney’s vernacular.