We present a series of 29 necropsies in which organic compounds (including benzodiazepines, barbiturates, antidepressants, phenothiazine, opiates, cannabinoids, meprobamate, digoxin and nefopam) were detected in arthropod larvae sampled on human corpses. No correlation was observed between drug concentrations in the larvae versus human samples. When tested, inter-larvae and inter-site variations of drug concentrations (i.e., within larvae when analyzed separately, and within anatomic sites when larvae were grouped according to their site of sampling) were enormous and not reproducible from one case to another, confirming that arthropod larvae are unreliable for quantitative toxicological analysis. Since drugs identified in maggots are always detectable in the cadaver too, we conclude that larvae analysis is of almost no interest for practical forensic casework.